I realised my interest after an afternoon working with my supervisor in a boiler room, both of us stripped to our shorts. There was a bit of banter and later in the afternoon he made comment on my cock becoming hard around him before suggesting I "come for dinner" at his place.
I realised what it was about and I was curious, when I arrived we sat at the kitchen bench and talked a bit about work over a few beers before he mentioned my earlier response and asked if it had happened before. It hadn't and I said so, and then he asked me if I was interested men sexually, as in doing the sorts of things I did with my girlfriend. My cock responded and I realised I was interested, but wasn't sure what to say because it hadn't crossed my mind until earlier that afternoon. However, when he asked if he could assist I said yes and very soon he was releasing my cock and invited me to do the same to him. I did so and very soon I was touching his cock, just holding it turned me on as much as his touch and when he offered a bj I nodded, he lifted me onto the bench and removed my trousers and shorts before getting busy. I gasped as he blew me, it was so different to what my girlfriend did and I nearly blacked out.
My curiosity was piqued and I was back the next evening, wow so good. A couple of weeks later I asked some naive questions about a rimming vid we were watching, and that became my next lesson...