If you really want to know, I can give you a few people ACTUALLY had me write on cakes where I work:
Doobie
Deuce (mother claimed it was a french name)
Mr. B
Peaches
King
Saturn (according to the boyfriend at the time, that's the car where the child was conceived and the mother wanted to name her that)
Shat (don't ask)
Quite a few I had are unfortunately not forum appropriate. The ones I listed are the more tame ones I've had over the nearly 17 years of working.