sphincter 

noun: one's pooper

gentlemen, rest your sphincters!

sphincter by the storm drains April 18, 2009

sphincter 

ring-like muscle found in the anus

From the South Park song "Mr. Hankey the Christmas Poo"
and won't fall in the toilet
coz he's just clinging to your sphincter
and he wont drop off and so you
shake your ass around and try to get it to drop in the toilet
and finally it does

sphincter by The Real Izzy December 28, 2005

sphincter 

the muscle that makes you poo

i had to get 16 stitches in my sphincter because vitt did me up the arse

sphincter by Morroco August 18, 2003

sphincter 

the circular muscle in your arse;
the poo-cutter

"aww that huge crap made my sphincter hurt"

sphincter by Bronoun September 20, 2004

sphincter 

possibly the coolest word in the english language
may hurt during anal penetration

omg sphincter!!!!
watch out for the sphincter, it might be hard to shit!

sphincter by Zaquie July 26, 2006

sphincter 

a muscular ring that closes a bodily opening

I had to shit the runs during the whole date with that babe last night. I kept thinking "Sphincter, don't fail me now!"

sphincter by King Shit January 19, 2003

sphincter 

muscle in ur bumhole that acts like a railroad switch tie to direct the output

1.if u tickle my bumhole, i may poop, or fart
2.I was peeing and my sphincter caused me to flatulate

sphincter by kal August 9, 2004