The act of stretching one's anus via toys with a 2" diameter for beginners up to 5"+ for experts. This can be an act of bdsm, fetishism, body modification or anal sex. The anus naturally stretches just like ear piercings, and after a few hours will return to its original size. This also helps to prevent hemorrhoids. It does not however have any negative side effects on defecation.
Boy, I sure am sore from all that anal stretching we did last night.