When one's diarrhea runs out. (sweet pun) One's sphincter and rectum continue to attempt to expel excrement unsuccessfully. Usually painful and uncomfortable.
Morgan: Wow what did I eat last night?
Mac: You bought burrittoes from that guy on the boardwalk again, and you drank a forty of old english.
Morgan: No wonder I've got dryaheevah, I can't poop anymore out I've just been dryaheeving all day!
Mac: Are you gonna be up our toga yacht party tonight?
Morgan: Oh god do you have any ice cubes? I think I pulled a muscle in my sphincter and my anus is on fire.