The best one I've ever heard was:
"WOMB FERRET"
Doesn't it just make you laugh
As a guy, I find the most blunt (cock, dick, penis) or the most general ones ("rubbed his hardness through the thin leather") are the best because anything poetic or too metaphoric just cries out "I'm a girl. Ewwwww you have a peepee"
*Cock and kisses from Muraki*
He loves you all so much he wants to cut off your heads and put it in his torso...Er, just watch the series ~Yami no Matsuei (Descendants of Darkness)
xx