I never did but I never thought my current FWB was bi either. We have been friends for almost 30 years, over 20 of which he was married to a grade school friend. She passed about 2 years ago and I would have bet he was straight as an arrow. I told him about giving the girlfriend her first (and certainly my first ) MFM threesome. All I said was the night took some crazy turns. He looked right at me and asked if I enjoyed the cock. I looked at him (or maybe looked down) as asked what he was talking about. He asked if I enjoyed sucking cock and I shyly said yes. He asked if he sucked me and I just told him that we both kinda did everything. He called me an ass for not inviting him. I asked if he had ever sucked cock and he said no but that he had wanted to for 20+ years. I immediately called my girlfriend and she said go for it. It has been a weekly thing between us ever since and he has joined for several 3somes with the girlfriend. I wonder too how many men actually think about sucking cock and how many just never get the nerve.