Due to no longer being able to continue intercourse do to injury, one would no longer have anymore "skin to give", hence having an empty "skin wallet".
I knew a guy named Enrique. This one time he was administering a female from the rear on a piece of plywood. His knees were so cut up he had to tell her "I can't finish, I got nothing left in the skin wallet".
by !@#$/^^/$#@!-'c August 16, 2018