[flashback to Marshall getting his hair cut by Lily's cousin:]
Marshall: So, um, just not-not too short, okay?
Amy: Oh, no, we don't even have to cut it at all. Could just give it some style.
Marshall: Oh, okay, yeah, that's great. 'Cause, um, when it gets too short, it starts to look weird. And I don't want to look weird when I'm up there, you know.
Amy: Ooh, I could give you some cool guy tips.
Marshall: I don't think I need advice on how to be cool, but yeah, great, lay that on me.