Yes--every word carries a different connotation with each reader, and sexual words are especially, um, loaded. But since we're talking smut here, I have to say that I do find "penis" to be too clinical--or worse, comical. (C'mon! It's a funny word!) "Cock" on the other hand, is hot--maybe in part because it's a little dirty, a little crude. But then hot does not necessarily equal romantic, so...

This is why I'm really curious to know specifically what context rashaka is wanting to use the magic-penis-word in. *eg*