The imaginary committee you're part of when you have tinyboobs.
Lindsay: Wow, my boobs are fantastic! I'm a 32DD!
Ashley: I just went up a cup size. 38C.
Hannah: Man, you two suck. I'm still a 36A. I'm part of the Itty Bitty Titty Committee.
Debra Messing felt that she was too flat chested, so she started the Itty Bitty Titty Committee so that she wouldn't be alone and be able to take over the world with small chests.