To give a boy a nickname of BJ?
I love both the names in this particular order, and yes he would have other nicknames with his shortened B name.
Also I listen to a podcast where BJ is their dogs name (also initials) and so it's become norm for me to hear it in a non sexualised context.
I don't live in the UK, and although I'm sure they still use it here I don't think it's as big a thing as it is in the uk? Although I could be wrong on that one!