Don’t wake her is a nice practice how to warm the girl even if she doesn’t want to. She is your girlfriend, of course you can play with her. So, if she doesn’t want to do anything pretending sleepy. It is just her business. Do what you want, but act gently and slowly cause she can wake up and you will have to start from the beginning. There is some hints: strap, stomach, blanket, nipple, underwear, undies… other action guess yourself. Good luck!