The involuntary response of ones anus to slam shut when taking an extremely large bowl movement. Although this may be a natural defense mechanism of the anus to prevent ripping, it generally causes severe pain and often bleeding.
Dude, I was hanging a giant loafer at my girlfriends the other day. I was about to blow an O-Ring when a peanut shard scraped my hole, and I did a wince clinch. I was stuck in there bleeding and crying for 20 minutes until I found one of her roommates heavy flow pads...
by Thedude78 September 19, 2013