look up any word, like the eiffel tower:
 
1.
A practice session of one instrument in particular. If you add "bi-" in front of the word, it immediately becomes ambiguous, hot, and often times, hi-larious!
"Hey Matt, do you have hot bi-sectionals today?"
by $$$ February 21, 2004
 
2.
When 2 band kids get together in bed. Usually referred to when a "trombone" is inserted into a "French horn"
Wil and Paige had 2 rounds of sectionals in bed last night
by Cheesehead425 May 19, 2014
 
3.
When you have to shit so much that you cannot physically shit all of it in one sitting, and need to take a break while the rest of the shit queues up in your intestines. The waiting period can be any amount of time between 20 minutes and a couple of hours, and usually the shit can be completed in two sections, though it may take three or more with epic shits.
"Just a sec guys, I gotta shit"
"Dammit Chris, what the hell is wrong with you? You just went to shit like 20 minutes ago!"
"Sorry boys, after all that shitty beer and T-bell last night I gotta take a sectional"
by Pineapple Hider September 09, 2009