Puking while giving a BJ?

Ok so normally I don’t have a gag reflex at all, but the other night I had a little bit to drink, and I was giving a guy a BJ and I kept almost puking the whole time. Sometimes I would even puke a little and then have to slurp it up before he noticed... it felt so disgusting. Any tips on preventing this!?? I’m just confused because I’ve never had this problem before but I guess the fact that I drank affected it?? Leave tips below! Thanks in advance !