OMG guys, in this vital conversation someone needs to introduce a bit of good sense.
First of all, ass is "culo" in Spanish. Not culon.
Culón (masculine) / culona (feminine) means "big-bottomed / big-butted", that is, someone who has a big ass. I guess that Padre Culón is a big-butted man who has had offspring. Not gonna search it tough...
Culero!!!! NO!!!!! I know that in some Latin American countries culero means coward or something like that, but in general terms a culero/culera is someone who tries to smuggle drugs by sticking them up his/her ass

.
Now, how would you translate Father Buttsman? Pfffff..... that's a tough one.
You sometimes translate English compound names with -man adding the suffix -ero in Spanish (milkman - lechero; postman - cartero; etc.).
Some other times it doesn't work at all. I already explained "culero", but there are other funny ones like "strawman" which can't be "pajero" (pajero literally means wanker/masturbator).
My suggestion is a freer, more refined translation:
Father Buttsman = Padre Don Culo
(which I'm sure
M.Sato will like since it's written exactly the same in Spanish and in Italian

).