[QUOTE=Triskadecamus]
How often do you use a plural for a body part that folks only have one of?
Tris
[/QUOTE]
Heads, hearts, tongues, penises, vaginas, noses, brains, livers, anuses, etc.
How about Fellatrices? Great word, that. Lovely ladies, too. 
That, I honestly believe, is a legitimate plural, like dominatrices, or the less titillating aviatrices.
Unlike my hack examples.