From a few hentai comics and video that I have seen, It wasn't an orgasm, but something that made her go to bathroom for some "Privacy"... although when the guy got there, she didn't mind any because she was so damn horny. Mind you when i say honry, I don't mean for it to be taken lightly, i mean like... Brink of Orgasm horny. Which would also explain the look on her face
