Penis fencing is a mating behavior engaged in by many species of flatworm, such as Pseudobiceros hancockanus. Species which engage in the practice are...

also practice so-called penis-fencing, in which two males hang face to face from a branch while rubbing their erect penises together. ...Perhaps the...

two such worms involves penis fencing, as each worm tries to inject sperm into the other with one of its two stubby penises, while trying to avoid being...

internally by copulation. Some of the larger aquatic species mate by penis fencing, a duel in which each tries to impregnate the other, and the loser adopts...

hermaphrodites. This particular genus engages in penis fencing. When the "winner" touches its penis to the "skin" of the other, insemination occurs, and...

Hermaphroditic flatworms reproduce by "penis fencing". Individuals "fence" with penises, attempting to use their penis to pierce the skin of the other and...

male or female, were born with what looked to be a penis. A female spotted hyena's apparent penis is in fact an enlarged clitoris, which contains an external...

the family Pseudocerotidae. This species has two penises, which it uses to engage in penis fencing, attempting to inject sperm into its opponent in order...

sexual conflict such as traumatic insemination, forced copulation, penis fencing, love darts and others. Female resistance traditionally includes reducing...

internally by copulation. Some of the larger aquatic species mate by penis fencing – a duel in which each tries to impregnate the other, and the loser...