Refers to the inevitable loss of blood flow to the penis while bicycling long distances, which numbs the appendage creating the sense that your "pee-pee" is asleep.
When you are so drunk you fall asleep after fornication with a partner, and forget mandatory bladder relief. While sleeping you release a raging torrent of urine onto "said" victim. Upon waking up to the smell of asparagus, you make a quick exit.