When a man's penis is fully erect and the foreskin still hangs off the dick end. Usually caused by excessive tugging of the foreskin or from having too many boys chew on it like bubble gum.
Son: "Dad? Why does your bald burrito look like shit?"
Dad: "Well you see son, I have a Foreskin Fortress!"
Son: "When I grow up, will I have a foreskin fortress?"
Dad: "Shut the fuck up son, and keep chewing your bubble gum!"