It's totally fine. I've been called way worse things than Booty. In fact, at one job that was my nickname until I could get my unruly, conduct disordered African-American dudes at the Hopkins methadone clinic under control, but given their interest in such matters I was torn between wanting to choke them out and feeling sort of complimented. Since I had red hair and I was about 25, we eventually compromised on Punky Brewster, since I wore pigtails a lot.
Now learning THEIR names? I asked one dude what his name was on day 2, and he said, "You can call me Pimp Daddy." I was like, "You sound like someone with a PO, maybe I should find your individual therapist and get your PO's name and give that person a call.... let him know what you're trying to do to a group therapist here."
Ironically, his name was John. Believe me when I say I pointed out the irony by saying "Really? Sounds like if any money is going to be exchanged, I'll be taking yours, not the other way around."
He was surprisingly amenable after that, LOL, the group tried a few more hazes, but I don't play fair, obviously.
Anna