accidentally slipped in
what happens to a guy when he is drunk and hanging out with a girl he likes and she likes him too and they have sex. the term is usually used to explain his innocence in the situation and therefore make him unresponsible for his actions.
what can i say, i was hanging out with X last night and it was late, one thing led to another and i accidentally slipped in- baby it didnt mean anything to me, really!