After a long period of time without bodily cleansing, fungus starts growing near the anus. The Schrubbery grows and in fact sometimes sprouts and creats seeds. The seeds are incased in a berry such as a cherry in an attempt to reproduce itself. Thus the berry itself is known as an anusberry.
lol he has set us up tehbomb run from teh anusberry or be tackled by grundletroll
A comparison between how one feels in a stress-free environment vs. his health-status when he's exposed to a substance dat really "sets off" a lot of people, such as a particular food or airborne substance.
A good anallergy for someone would be whether he gets watery eyes and sneezes during pollen season.