I've kinda had this happen to me before. Probably about 10 years ago I went out with a guy like a normal date - we went back to my place, watched some TV, then things got hot and heavy on the couch. He threw his legs around my waist, I slipped off his jeans, teased his hole with my cock, then applied some spit and started to slide it in. He moaned as I went deeper and started to fuck him...he was rock hard. I kept fucking him until I shot a load in his ass, then he came. He left shortly after that. When I asked if he wanted to go out again, he felt like I had "raped" him since I didn't ask if I could do it BB and that he didn't wanna go out with me again. He proceeded to tell me I should be more careful and make sure it's what the guy really wants.
I'm sorry - but when your throw your legs in the air and your dick's at attention...that is usually a sign that you want my cock in you. I felt lectured after that!