Robin: You only get one shot at losing your virginity. And even though I just barely had sex, it counts.
Lily: What do you mean just barely?
Robin: Well, he didn't dive all the way into the pool, but he... splashed around in the shallow end.
Lily: Then you didn't lose your virginity to him. Just barely doesn't count.
Robin: Yes, it does.
Lily: No, it doesn't.
Marshall: Yes, it does.
Lily: No, it doesn't. It doesn't count. End of story.