Every guy has a fantasy about seeing two girls together. It’s a double-your-pleasure, double-your-fun kind of thing. But when those two girls are sisters, the allure is magnified a hundred fold. Maybe it’s the lure of the forbidden, or simply because the lines of platonic and romantic love are blurred. Either way, it floods the body and mind with all sorts of senses and this allows one’s imagination to run wild.

These days, the biggest celebrities are the ones that come from famous families. There are the Kardashians, the Baldwins, and even the Duggards. And in the digital age, there is great pressure for members of celebrity families to one-up each other in order to stay relevant. The biggest trend right now are pics of celebrity sisters coupling.

Some sisters mess around because they’re being goofy, whereas others are looking to be controversial. But where should the line be drawn between fun and perverse? With gender fluidity, pansexuality and every other permutation out there, it’s difficult to discern what’s acceptable and what’s not. Since a picture is worth a thousand words, we’re going to let you be the judge. Here are 15 pics of celebrity sisters getting touchy-feely. It’s for you to decide if it’s too much – or if it’s just right!

15. Kendall and Kylie Jenner

At first glance, this pic of Kendall and Kylie Jenner just looks like two sisters laughing and having fun. But once you look at the proximity of the two, you start to notice certain details that make you think otherwise. A careful look at Kylie’s body language reveals a different story. She is pulling Kendall into her, and she has her face turned up to her sister with her lips parted. Kylie looks like she’s about one step away from French kissing her sister. We wouldn’t be surprised if that’s exactly what happened next, since they come from one crazy family that will do anything for attention.

Kendall has a major career going for her, as she has modeled for big names like Victoria’s Secret and Estee Lauder. However, Kylie is a little more desperate. Her career is still stuck in the celebutante phase. Thus, she needs shocking photos like this one to keep for followers and further her “career.”

14. Mary Kate and Ashley Olsen

Who hasn’t fantasized about the Olsen twins getting it on? Well, here’s a photo to fuel your fires! Mary Kate and Ashley are in a total lip lock, and it’s hot! Who cares if there’s a guy sitting in between them? He’s got the best seat in the house! The sisters have always been close, but this brings it to the next level. Over the years, they’ve been photographed hanging all over each other in revealing clothing. This is the next logical step. But giving each other a full-on kiss is hardly the most scandalous thing about the two. Between dating men twice their age, eating disorders and the whole Heath Ledger brouhaha, we’d say this is pretty tame. The most embarrassing thing for the sisters will be once their sister Elizabeth Olsen’s acting career really takes off. She’ll be regarded as a serious actress, while the twins will just be remembered for their child acting on a sappy sitcom.

13. Paris and Nicki Hilton

This photo of Paris and Nicki Hilton was made to make the girls look like lovers. From the barely-there outfits to their sultry stares, the girls are trying to get viewers excited by the taboo. The posing of the sisters is especially provocative. Nicki’s legs are wide open, and her hand is splayed in between. Her head is turned into Paris. Paris is never one to by shy, as she is dominating Nicki by standing above her. Paris looks directly into the camera and dares us not to be turned on by this taboo.

Nowadays, we bet the girls are embarrassed by this pictorial. Nicki is now married to a Rothschild, and Paris has been trying to rehab her image ever since her incarceration for drugs. But the Internet never forgets…

12. Dakota and Elle Fanning

Dakota and Elle Fanning are all over each other in this pic that Elle posted to Instagram. Dakota in lounging backwards on a couch, while Elle is splayed across her. Dakota looks tipsy, while Elle looks like she is hamming it up for the camera. If we didn’t know any better, we’d say these two were lipstick lesbians rather than sisters. But that’s the whole point of this pic, isn’t it? The sisters are yanking our chains to get us riled up – and we love every second of it. The best part of the pic is that it blurs the lines between off the cuff and staged. On the one hand the shot looks natural because Dakota looks so out of it. But on the other, it looks like it was choreographed because of the beautiful cityscape in the background and Elle’s purposeful posing.

11. Sailor Brinkley Cook and Alexa Rae Joel

Christie Brinkley’s daughters Sailor Brinkley Cool and Alexa Rae Joel, have made a splash in the media since posing for the latest Sports Illustrated Swimsuit Edition. This shot is taken from Sailor’s own Instagram account and shows the girls baring just about everything side by side. They are topless on lounge chairs, and are showing off how curvy their breasts are. But their bottoms aren’t bad, either! Both are sporting cheeky styles – pun intended! We can’t be sure, but we might even spot some sand on Sailor’s rear end which makes us wonder what the two girls were up to before this pic was taken. Sailor is definitely the aggressor in this shot. Alexa is staring off into the sunset, but her sister is looking directly into the camera. It’s like she knows she’s doing something forbidden, and wants to make sure we are watching her. Count on more pics like this from the sisters. They’ve already admitted to being “obsessed” with each other, and are definitely looking to see their stars rise.

10. Khloe Kardashian and Kylie Jenner

It looks like Khloe Kardashian and Kylie Jenner are having more fun as blondes than brunettes! Khloe is planting a big kiss on Kylie’s cheek, and has probably been whispering her sweet nothings to her all day while the two of them were getting intimate on a picnic blanket. Kylie doesn’t seem to mind in the least. She has a wide smile on her face, and her eyes are closed in utter content.

Are the sisters getting too touchy-feely? The rumor mill is definitely churning, and it’s largely due to the fact that Khloe is the one doing the kissing. She’s the most masculine of all the sisters in the Kardashian/Jenner family, and this has led people to speculate that she swings both ways. She could definitely be exploring the fairer sex here with her sister.

9. Jessica and Ashlee Simpson

Jessica and Ashlee Simpson are having too good of a time in this shot taken on the red carpet. They are literally body to body. Jessica is squeezing Ashlee’s bottom, while Ashlee looks like she’s about ready to give Jessica’s hair a playful tug. Are they hamming it up for the camera, or enjoying themselves a little too much? It’s hard to tell by looking at their facial expressions. The sisters’ mouths are open in an expression of ecstasy, like they are egging on their audience.

The Simpson sisters join a long line of sisters who have been rumored to be a little too close. The Barbi Twins set hearts afire with their racy pictorials, including ones for Playboy. Ann and Nancy Wilson of the band Heart dodged rumors of being secret lovers for years. And Lena Dunham has even admitted to forcing her sister to kiss her for long periods of time when they were children.

8. Sienna and Savannah Miller

Sienna Miller is known for her famous hook-ups. First, it was Jude Law who cheated on her with the nanny. Then, it was her affair with billionaire actor Balthazar Getty. She’s also been linked to Sean Combs, Josh Hartnett, James Franco, Jamie Dornan, Orlando Bloom, Hayden Christensen and Daniel Craig – as well as a slew of lesser known names. We have a sneaking suspicion that she’d be called a “tramp” if she didn’t have that lovely British accent. However, there’s one more person that she has locked lips with. It’s her sister, Savannah!

The interesting thing is that when we looked at these pics of celebrity sisters hooking up, it’s usually the less famous one that does most of the heavy petting. But in the case of the Millers, it’s Sienna who is doing the pawing.

7. Kristina and Karissa Shannon

Kristina and Karissa Shannon have made an entire career out of being sensual with each other. The world came to know them when they lived in the Playboy Mansion and appeared on the E! reality show The Girls Next Door. They later posed as centerfolds in Playboy’s summer issue of 2009. Aside from being two of Hugh Hefner’s girlfriends, they’ve been linked to Spencer Pratt and Heidi Montag as Karissa said she made a "tape" with them. Meanwhile, Kristina has been linked to Playmate Ida Ljungqvist. But their hottest hook-up has got to be with each other. The two love being wild and crazy, and often tease their fans by touching and kissing one another. This pic of them is typical of the sort of action they like to get in to.

6. Miley and Noah Cyrus

Miley Cyrus is a self-admitted pansexual. A pansexual is someone who does not limit themselves in their sexual choice to biological sex, gender or gender identity. Apparently, pansexuals don’t exclude family members from their sexuality, either – as evidenced by this pic of Miley Cyrus getting up close and personal with her sister Noah. We’re all for exploration, but this is a little too much. Miley seems to be dominating her younger sister, and we bet Noah doesn’t know any better. This is one shot of celebrity sisters getting touch-feely that isn’t hot – it’s disturbing. Of course, that’s probably just how Miley wants us to interpret it. She’s not happy unless she’s pushing norms. Miley is one weird bird, and with Noah coming of age, we can see her implosion coming a mile away.

5. Lily and Ruby Aldridge

Lily Aldridge is so luscious that we can’t blame her sister Ruby for wanting to plant a big ol’ smooch on her. Aldridge is such a hot commodity right now that it’s only natural for her sister to be just as enamoured with her as we are. The Internet has been swirling with rumors, though, that Ruby is a little too attached. People point to her “butch” appearance as fodder for the assertion that she has a lesbian crush on her sister. We’re pretty sure that is all nonsense, but we can’t help but look at Lily’s body language and wonder if maybe there’s something to the rumors. Lily is pulling away from her sister, instead of embracing her. Maybe she doesn’t want to get her makeup messed up – or maybe she just isn’t in the mood for hanky-panky from Ruby. Lily has an image to maintain, not to mention a husband and baby to care for.

4. AnnaLynne, Angel and Rachel McCord

AnnaLynne, Angel and Rachel McCord are looking like three’s company in this pic. They’re on the beach, and are in a three-way hug on the volleyball court. How sweet! There’s nothing wrong with this pic, except when you take it in the context of other photos we found of AnnaLynne and her sisters. Out of all the celebrity sisters we looked at, AnnaLynne is caught in kisses with her sisters the most. And we’re not just talking pecks. Some are full-on smooches. Add to that the fact that AnnaLynne is a survivor of a sexual assault, and that her boyfriend (Dominic Purcell) is 16 years older than her, and people are wondering if she has some confusion to work out.

3. Hilary and Haylie Duff

Hilary and Haylie Duff put new meaning to the term lipstick lesbian with this pic! Hilary has left her mark not once, but twice, on sister Haylie. We understand a kiss on the cheek, but the kiss on the ear has tongues wagging about these two. Hilary even looks like she’s gearing up for a third one. Perhaps on Haylie’s neck? Hayley looks like she’s enjoying the whole thing. She’s screaming – but in a good way. Maybe she’s ticklish or maybe she’s getting her jollies. Heck, she’s probably just happy that someone is paying attention to her since her career is nonexistent. As for Hilary, it’s good to see her let loose. After she stopped being “Lizzie McGuire,” she became too serious for her own good. If she wants to have some naughty fun with her sister, we say “go ahead.”

2. Cara and Poppy Delevingne

Cara Delevingne is a hot commodity right now. And her appeal is magnified when we see her being kissed by her sister, Poppy. People would probably just look at this kiss a friendly peck on the cheek from sister to sister, were it not for Cara’s legendary hook-ups. Cara has been linked to men and women, as is the current poster child for gender fluidity. Thus, it’s not a stretch for most to think that there has been some “experimentation” between the sisters.

In the UK, the Delevingne family is known for its scandals. Their father is regarded as a merciless social climber. Their mother is famous for her drug addiction. And the girls in the family (Cara, Poppy and Chloe) were given a posh upbringing complete with private schools and jet-setting. Close family friends includes the royals, the Spice Girls and Kate Moss. In fact, Cara is said to be the “new Kate Moss.” This is not only due to her heroin-chic looks, but the fact that Cara can party even harder than Moss.

1. Gigi and Bella Hadid

Gigi and Bella Hadid are getting comfy-cozy in this pic. The two of them are lounging on a hotel bed with their arms intertwined. Bella is resting her head on Gigi’s breast, and both have a dreamy look in their eyes. It would be a cute picture of sisterly love if only they weren’t so scantily clad. And upon close inspection, it looks like Bella’s hand is between Gigi’s thighs. Is this too close for comfort? You be the judge. Either way, it’s fun to analyze.

Of course this shot is just one of many provocative pics that sisters have taken. Other include them in bras while modeling for Victoria’s Secret, kissing at fashion shows, and lying together poolside. Obviously they’re close and have a bond, but they’re also smart – they know their careers magnify every time they are photographed together.

Sources: Wikipedia, dailymail