A mysterious lichen that grows from the base up along the length of some rather unwashed male cocks. It is thought to be caused due to repeated contact between the penis and couch cushions, or possibly contact with the vagina of a femenazi.
Joey: *fucks couch*
Dema: Hi joey!
Joey: *fucks dema*
Dema: What is that delicious-looking lichen growing on your cock?
Joey: SHUT UP FAG