We were with a couple and I went down on his wife. Things seemed very slippery and it took me a while as a newbie to realize that most likely she had had unprotected sex with either her husband or someone. I was pretty sure that the slippery and taste and sex smell was from sperm. It worried me that I could be exposed to STI but nothing happened. Surely if you are at a club you should also condomize with your wife respecting others who might be with her later or might lick her later.