DS also used boobie to refer to nursing. It didn't bother me, to be honest, but we had my in-laws coming for X-mas, and I just didn't want to deal with the hassle. I don't think they know I'm still nursing. So the week before they came, we started calling it snack. Well, he had adapted to using snack before the in-laws (I usually call them out-laws, to be honest, since DH and I aren't actually married!) even arrived. In their hotel room the day we picked them up he was saying "want snack, snack please", and my MIL was running around finding things to offer him as a snack! It's turned out to be very discreet. it allowed me to say "oh, I'll just go get Andrew a snack" and take him away to nurse. Which I don't bother doing with anyone else, but with my in-laws, like I said, I just don't want the hassle, so I'd rather keep up the pretense. I know there are people here who will feel I ought to be educating my in-laws about the benefits of EBF, but it just isn't going to happen. I educate everyone else I come across by nursing pretty much anywhere and everywhere, but not them. Luckily they live out of town!
the only time we hear boobie now is if I offer him a regular snack when he'd rather nurse, he will inform me that "no want it, want boobie snack!".
So, yes, you can change what you call nursing, and it amazed me how quickly we managed to do so.