First Hand Job
For me, because i'm more straight then bi, I gave my best friend a hand job. I know that doesn't sound like a big deal, and it's not. But, I never given someone else a hand job until my friend. He wanted to be wraped up in plastic wrap so he couldn't move. Just his thing. But then, I just pulled back the plastic, undid his belt and zipper and exposed his cock. I just rubbed his dick until he was hard. At this point in knew I was all in and continued playing with his dick. I felt really good, knowing I was in full control of what was going to happen. I got some lube and just kept jerking until he let go of a huge load of hot cum, felt good all over his dick.
Reading your hand job experience made me quite excited and got me thinking of my own experiences.
Despite having spent many hours handling my own cock over the years, to actually touch and then take hold of another guy's firming cock for the very first time was quite a surreal moment & and to run my hands all around it as I began stroking took me to a highly erotic state :-). To feel and watch it grow just added to the excitement. It was a similarIy erotic and stimulating experience the first time I took an erect cock into my mouth, with the added fear & excitement he may cum while I was sucking him.
Both of these 'firsts' were also in public - raising the excitement levels even higher!