Too close for comfort? Khloé Kardsahian and Scott Disick have been playing up their flirtation for a story line on Hulu’s The Kardashians. “It gets people talking and gets more eyes on the show,” says an insider. But the sexy banter between the reality stars — who’ve stayed close following Scott’s 2015 split from Khloé’s sister Kourtney — isn’t all for show. “It happens when there are no cameras around, too,” says the insider. “They like to flirt.”

The dynamic duo were once at odds, with protective sis Khloé even slapping Kourt’s then-boyfriend in a 2009 episode of Keeping Up With the Kardashians. But in the years since — as Scott went on to have three kids (Mason, 13, Penelope, 11, and Reign, 8) with Kourtney — they’ve become besties, prank buddies and fervent flirters, with Khloé even admitting they once held hands for photogs to “[mess] with everyone.”

Recently, however, the fun flirtation has crossed into cringe territory. On one episode, Scott, 40, joked that he wanted to sleep with Khloé, 39, for his birthday, and claimed he wants to date someone with “all [her] characteristics.” While the insider says it’s unlikely the pair will take things any further, they love to push the boundaries. “They know it drives Kourtney nuts and is a great story line,” notes the insider. “They think it’s quite funny and love playing around with it just for the sheer shock value.”