The feeling one gets that one must urinate, starting very weakly yet increasing tremendously the nearer one approaches a bathroom, usually experienced when in one's car: the nearer one's driveway, the more urgent, and the nearer the bathroom, more urgent still.
When people shit on themselves in anticipation of someone else shitting on them. People think this will shield some criticism, but really it just gives assholes better material.
"I know I'm not a very good singer, and my massive love handles detract from my already terrible singing, but please be respectful while I attempt (insert Miley Cyrus song here)"
Most crappy youtube performers take nice big anticipation dumps in their self-descriptions
A bottle of hard liquor that someone purchases while still owning a partially consumed bottle of the same or similar liquor. The bottle is purchased with the thinking that the partially consumed bottle will soon be fully consumed and the person doesn't want to be put in the situation where they've run out completely.
"Don't you already have half a bottle of Jim Beam at home?"
"Yeah but this is my ANTICIPATION BOTTLE. I don't want to run out. It's only Friday!"