The two got to only first base (kissing), which is about the only base that anyone can agree on anymore. ''I don't understand the base system at all,'' Jesse said, lying on the floor and staring at the ceiling. ''If making out is first base, what's second base?''

''We need to establish an international base system,'' Brian said. ''Because right now, frankly, no one knows what's up with the bases. And that's a problem.''

Jesse nodded in agreement. ''First base is obviously kissing,'' Brian said.

''Obviously,'' Jesse said.

''But here's the twist,'' Brian said. ''Historically, second base was breasts. But I don't think second base is breasts anymore. I think that's just a given part of first base. I mean, how can you make out without copping a feel?''

''True,'' Jesse said. ''And if third base is oral, what's second base?''

''How does this work for girls?'' asked Ashley, the 17-year-old junior. ''I mean, are the bases what's been done to you, or what you've done?''

''If it's what base you've gone to with a girl, you go by whoever had more done,'' Jesse told her.

''But we're girls,'' Ashley said. ''So we've got on bases with guys?''

''Right, but it doesn't matter,'' Jesse said. ''It's not what base you've had done to you, it's what bases you get to.''

Kate shook her head. ''I'm totally lost.''

''See how complicated this is?'' Brian said. ''Now if someone asks you, 'So, how far did you get with her?' you have to say, 'Well, how do your bases go?' ''