A vagina with extra-double long skins (Roast Beef Curtains) that hang down potentially to the ankles of the female in question. Roast beef curtains to the ankles = Rankles.
Yo man, I was about to smash out that chic Keisha I told you about until I got her panties off and was disgusted by her Rankles! They were so long and beat-up I didn't know how she was able to walk without tripping over them!!!
When a guy's junk sticks to the inner part of his thigh (usually on a hot summer day)
Hey Brian, can you come over here relieve me of my rankle? It's hot as hell and I can't do it myself because I have groceries in hand; be gentle (think band-aid - nice and easy).