A special type of celebration that occurs after you have taken a gigantic shit. The method of action is, as soon as the disaster falls, you jump in the air as high as possible with a clinched fist while shouting "YEEEEAAAHHHH!!!".
The bathroom floor was painted brown and dripping due to John's most recent celebshit-tion.
Never celebshitate if you have diarrhea. Amanda figured this out the hard way.