To borrow from the great comedic folk duo, Flight of the Chonchords “Yeah, you sexy hermaphrodite lady-man-lady, with your sexy lady bits, and your sexy man bits too, even you must be into you-oo-oo.” Hermaphroditism is common in marine invertebrates and the, flatworms are no exception. Certain species of flatworm engage in a behavior called penis fencing. Both swordsmen in this sexual fight are equipped with two-headed dagger-like penises. The champion is the individual that inseminates the other by jabbing them. The sperm is absorbed through the skin, and makes its way to the ovaries. The loser is fertilized and stuck with a bunch of crying little flatworms demanding energy and time.
Losers and winners are not always the case in hermamphrodites. Often both are winners in which a mutual exhange of sperm occurs.