Xander: Willow, did you remember to tape Biography last Friday?
Buffy: See, I told you. Old Reliable.
Willow: Oh, thanks.
Willow: ‘Old Reliable’? Yeah, great. There’s a sexy nickname.
Buffy: Well, I-I didn’t mean it as…
Willow: No, it’s fine. I’m ‘Old Reliable’.
Xander: She just means, you know, the geyser. You’re like a geyser of fun that goes off at regular intervals.
Willow: That’s Old Faithful.
Xander: Isn’t that the dog that, that the guy had to shoot…
Willow: That’s Old Yeller.
Buffy: Xander, I beg you not to help me.
Buffy the Vampire Slayer — Season 3: Episode 16 — “Dopplegangland”