AF or not? TMI

So AF came a little early this month by one day. I had spotting the first day then medium flow then back to spotting and last night since there didn't seem to be anything going on AF wise my husband and I had some fun. Well afterwords when he was cleaning off there was this thick pinkish stuff on him at the very tip. What exactly is this stuff? We are both clean as far as STD/STI's go so it was weird to both of us.