Kylie Jenner can't keep her paws off Tyga!

The duo flew out of town over the weekend, and while lounging around at the airport, she snuck up on her boo and took a Snapchat video -- while she was on top of him. "What is this guy doing?" she said as she walked up to the rapper. Tyga smiled, and in the very next Snap we see Kylie's perky booty sandwiched in between Tyga's legs. After making out for a few seconds, Kylie manages to say, "I think we fit."

Kylie also posted a video of her massive new diamond ring, and despite referring to Tyga as her husband and posting a photo of the two the other day with the caption "Mr & Mrs," she's been telling friends the duo are NOT getting hitched anytime soon. "Kylie has brought up marriage with Tyga to her friends lately, both jokingly and seriously," a source told E! News. "It wouldn't happen now but she's been thinking about it more and wants a future with him."