It was in A-minor
Because they're practicing to be men.
Men jiggle the nozzle afterwards.
Thought of this one on my own while playing WoW a couple days ago and I'm pretty sure it hasn't been told before. I like corny jokes. I Googled it and didn't find anything (:
A minor.
He was doing crystal math.
He resisted a rest.
He was caught playing in A minor.