What did Alvin want for Christmas in The Chipmunk Song?

Alvin kept interjecting that he wanted a hula hoop. Dave got progressively angrier at this, though he should have been thanking him, given that coming up with a different rhyme for "loop the loop" could have been problematic. Maybe that's why Dave was so angry: he'd slaved for weeks to come up with something, and here's Alvin, effortlessly interjecting some improvised lyrics that fit the rhyme and scansion perfectly ... I'd have been a little miffed myself.

Alvin also must have wanted a harmonica badly enough that he didn't feel safe trusting in anyone else to get it for him: "It's a present, Dave, from me to me."