Can be prevented by: regular kinky monkey sex with dirty kinky sluts, eating out lots of pussies, and stimulating your shaft and anal canal simultaniously (@ the same time).
Racheal: "Let's have sex!"
Racheal: *pulls down craig's pants* "Eww is that shit a foon?!
Craig: "Yeah I have Fds (Foon Dick Syndrome)." *sad*
Racheal: "Lets fuck it back to normal!"