Case 1: He is gay and thought he could get laid. Tried to hit on you, you rejected him, he covered it up by saying he was tryna see if YOU were gay? Bull**** excuse.
Case 2: He was just drunk and horny. Too embarrassed and doesn't want to bring it up.
Case 3: He might have thought you were gay?? And was testing you? Which is a stupid and disrespectful way to do so.
I am leaning towards the first and second.