fellatio: Oral-penile sex.

female-superior position: Common sexual position, wherein the woman lies on top and the man lies on bottom.

foreskin: A sheath of skin that surrounds the glans at birth and opens at the top; may be surgically removed in a process known as circumcision.

frenum: The strip of skin connecting the glans to the shaft on the underside of the penis.

frottage: The practice of two men rubbing their bodies against each other, usually until climax; considered a safe form of homosexual activity.

full laparotomy: Form of female sterilization involving major surgery; see tubal ligation.