You're kissing and doing the hanging out thing, just ask her to make it official.
If it was me, I'd ask just after a kiss, while still close with a cute grin. She'll laugh and say yes.
Kayla, hand on the leg? Thigh touching? Honestly..

Don't play games, just ask. And ye shall receive.
Of course, she might say no, because girls are weird. Sorry. I'd give you a 98% chance though, if thats any help

Luck!