Has KoKo gone loco?!

Khloé Kardashian took to Instagram on Thursday, June 22, to share two photobooth shots of herself hanging out with her younger sisters Kendall and Kylie Jenner at the Season 10 anniversary party for Keeping Up With the Kardashians. Sister selfies are always cute, but it’s what Khloé, 32, and Kylie, 19, are doing in one of them that is raising eyebrows on social media.

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My babies for life! 😍😍

A post shared by Khloé (@khloekardashian) on

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In the ladies’ saucy pic, the cosmetics mogul is licking Khloé’s left boob as the Strong Looks Better Naked author pouts her lips for the camera. Kendall, 21, poses with Khloé in the photo underneath. While she isn’t attempting to taste her older sibling’s chest, the supermodel is seen biting onto a lock of Khloé’s short blonde hair.

Naturally, the Revenge Body host’s millions of followers had a lot to say about her provocative post. “Be careful! Your family wants to eat you!” one fan joked, while several others seemed rather disgusted.

“Sisters should not be acting like this! SO inappropriate!!” one fumed, while another wrote: “OMG i’m about to puke. This is so weird on way 2 many levels.”

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One fan was rather frank in their critique of Khloé’s interaction with Kylie, asking, “WTF is wrong with you girls?!! Who licks their sister’s boob???”

This isn’t the first time the reality star has acted somewhat inappropriate with her family members. In 2015, she cozied up for a selfie with Scott Disick — you know, Kourtney Kardashian’s now-ex-boyfriend and baby daddy — with this caption: “The Lord and The Lady.” And in a 2014 episode of Kourtney and Khloé Take the Hamptons, they shared a bed after Kourt kicked Scott out of their bedroom.

Insiders have previously told In Touch that Kourtney, 38, has never been comfortable with Khloé and Scott’s close relationship. “She’s jealous because her man and her sister are spending so much time together,” a source has said. “She’s not happy about the situation. It’s driving her nuts.”