I don't have it but someone else does. Here are the details from a site about how can I tell the difference between a mole and skin cancer.
"I have a mole that I believe has been with me since birth. It is located near the base of my spine, between my buttocks, and approximately two inches behind my scrotum. About once a day the mole excretes a dark and very smelly material. Sometimes the material is very large and stiff, while other times it's runny like water. It always has an awful odor.
I usually have to clean this mole up after it excretes stuff, and then it's typically okay for the next day or so. Sometimes, it will be two or three or even up to seven days before it releases the dark smelly material. Should I be concerned?"