How do I ask my friend to with me?

Well, We're both 15, and a few nights ago, he stayed the night. We watched some , and we've talked about and we know each others size. After he fell asleep, I reached over and put my hand on his , and I moved my hand down to feel it. that made him hard. later, he reached down and put his hand in his pants.(still asleep) he put his leg on top of mine, and I reached over and started to give him a hand job. (he stayed asleep)He lurched before he ed, so I stoped, afraid he woke up. later, he reached over and wedged his hand down my pants and felt me. he didn't do anything else. he got up early and left that morning. How can I ask him to with me??