We certainly don't act this way with our brother-in-law!

Scott Disick and Kendall Jenner looked quite cozy as they waited for their ride outside Nobu Malibu following Rob Kardashian's birthday bash over the weekend, and it's more than a little weird since he has three kids with Kenny's half sister Kourtney Kardashian. While we highly doubt anything is going on between them, their flirtatious behavior makes us more than a little uncomfortable.

Apparently it was OK for The Lord to attend the gathering, but not Rob's girlfriend Blac Chyna, as she was noticeably absent. Poor Rob looked like he missed her as he sat shotgun while catching a ride home with Kim and Kanye. We wonder if Ye dropped him off at his lady love's, or whether he was forced to sleep alone at his own crib.

Kris Jenner and boy toy Corey Gamble left by themselves, and we have a feeling we know what was on their agenda for the rest of the night!