to take a crap in the water tank of a toilet so that when it is flushed next time dirty water runs down into the bowl. almost impossible to clean out if one doing the high topping has the runs.
Man, I went over to my ex's house and left a high topper in her bathroom.
To deficate in the tank portion of a toilet causing every flush there after to be totaly fowl.
Pick someone, not someone you hate but someone you just dislike. Go to their house or personal office toilet and drop a high hard one in their toilets tank. The High Topper the gift that keeps on giving.