"Keith Boadwee, Adjunct Professor of Fine Arts at the California College of the Arts, and visiting faculty member at the San Francisco Art Institute ... part-fills his rectum with (non toxic) water-based paint using a rubber hot water bottle with an attached plastic tube. Then, by carefully positioning himself near a large blank canvas placed horizontally on the art-studio floor, he is able, at the appropriate moment, to eject and direct a constrained jet of paint. Thereby rapidly creating one-of-a-kind artworks with an appositely chaotic and spontaneous feel."
ETA: OK, now it's too early in the morning for this kind of thing (in my timezone anyway)