A penis so huge, it is comparable to the mighty might of Hercules himself! A herculenis is the superlative and ultimate measure of width, length, bounciness and elasticity (when flacid), rigidity and speed of movement (when erect.)
Dude 1: Dude, can you imagine waking up and seeing a herculenis dangiling above your face?!
Dude 2: Ewwww! Dude, i'd punch it like a punching bag!
Doctor: So, what seems to be the problem here?
Man: I have such a herculenis that when i was riding my bike naked, it got mangled in the chain!
Doctor: Jesus Christ! Thats a hell of a herculenis!