He is probably embarrassed because he thought you were going to have sex. If you are interested in him romantically, please tell him.
You can say in a light hearted way "I was so suprised what happened after the party the other night! It was a nice surprise, but it threw me for a loop. I'm a slow mover and to me, sex means it's the beginning of a relationship. Sex is a big step. If this is something you are interested in, I would love to see more of you"
This is what you can say if you want to move things along with him.
If you just want to be friends, you can say "I miss our time together, but I don't want things to be weird because we made out. Can we still hang out and be friends?"