Read the damn forums! This has been discussed in depth. But guess what, Just cos they are borderline sex workers, doesn't mean they don't like anime, sushi, or shopping. I'm borderline psychotic, and I like those things too. Well not Anime or shopping, but you get my point.
Sorry mate, but to me "cock" and "dick" have several meanings.
In your case it's not the dangling appendage meaning, but the other one that is often used in conjunction with the word "head". As the high rolling owner of an advanced educational institution (which I presume is an Eikaiwa), you should get the meaning.