Advice needed please! - What shall i do? Platonic male friend crossed the line?

I trusted a platonic male friend not to do anything while we were sharing a double bed. If i hadn't of been trusting of him I would never have done it. I realise now i may have been naive as I could never have been sure of his thoughts, but i treated him as I would my girlfriends. Everything was ok until i rolled over in the night and disturbed his sleep. He proceeded to, whether intentionally or not, reach out and put his hand on my bum. I obviously shrugged him off but the hand moved back to my knee. I then sat up and shoved him to wake him up, he kind of mumbled nonsense and rolled over and went back to sleep. Nothing else happened. When i told him the next morning he couldn't remember anything and seemed embarred, he apologised but just tried to p it off jokingly. I do believe he was genuinely asleep, but it still freaked me out a bit. He has never said he has had romantic feelings for me, but looking back now there are some signs but I don't know if im being paranoid and making too much of this. I don't know what to do next, shall i make it clear im not interested in anything other than friends? Or shall I leave it be and just learn from this i.e. not to share a bed with him again so as to not encounter anymore subconscious desires?! I don't want to make the situation worse, but I don't want to bury my head in the sand either. Any helpful advice would be very much appreciated. Thank you