Apropos.

Dear Really Enthusiastic Math Kid,

Wow. You really love this stuff. I can tell. And trust me, no one appreciates the rush that comes from doing a problem on the board in front of our class more than I do. It's a great feeling, I know. However, you seriously need to consider toning it down. You're at least 21, and waving your hand up and down while literally bouncing out of your seat with joy for a chance to demonstrate every question the class members ask to see is a little much. I think it'd be different if you were right more than 50% of the time, but please consider sparing us your long-winded, public apologies about why you went wrong and let someone else try. You aren't the TA. After the fourth or fifth loud, self-righteous solution you express on the board, I'm sure you can imagine that things start to get a little old, and I start to imagine shoving the chalk down your overly enthusiastic throat.

Tactfully,
Quiet Blonde Girl from the Second Row