My first experience was using a dildo on a straight buddy. We were both just a few years out of college and not really "experienced" about sex except in the "bang the fuck out of some chicks" -- i.e. not used to or very good at intimacy and long play.
Anywho, we were drinking at a local hangout and talking trash when out of the blue he confided he liked to have his gf use a dildo on his ass, to stimulate his prostate. One thing led to another and, well, even though I'd only been with a few guys and he'd done nothing more than jack off sessions with a few of us, I said I'd be happy to help him.
Next thing I know we were back at his apartment and stripping and laughing as guys do -- a bit nervous, a bit drunk, a lot horny. As we jumped onto the bed even he commented about how fucking hot we looked together.
Anywho he knew what he needed and wanted and quickly my tall, sexy, bearded, muscled bud was laying back with a pillow under his hips and his legs open. He handed me the dildo and then lubed his hairy hole, which even though I had no experience with this sort of thing, I could not help admiring it. I mean, it was the perfect site -- a manly guy, a manly hairy hole that was hungry for attention.
I fucked him with the dildo for a good 15 or twenty minutes, getting deeper with each stroke and making him crazy with verbal about me watching his gf fuck him, me eating her, and god only knows what else I said.
I could tell by the way his hips were bucking he was about to cum and so I told him I was gonna turn us queer and bent over and licked his balls for a moment. My bud fucking exploded like you would not believe, his cum landing on his beard. He took a deep breath and together we pulled the dildo out of his hole ever so easily. It was so fucking hot seeing his hole gape from the dildo use, I can't explain it.
He then asked if I was going to get off and I said "definitely" and he said, "Why don't you straddle my hips and jack." I was kind of floored by the offer but did so. As I jacked we kept eye contact and though it took a bit of time he started rubbing my chest and stomach, then kind of cupped my balls. I wasn't sure where I was supposed to cum and so I started to roll off him, but he kind of clamped down on my legs and so I stayed there until I came like a gusher all over his hairy stomach.
We played about once a month for over two years and each time we got better at using the dildo on him. I even dildo-fucked him the night before his wedding. The only reason it ended is that he moved.
What was interesting was that while it was man 2 man sex (i.e. gay/bi, whatever you want to call it), it truly was the straightest "gay sex" you could imagine. I know, weird, weird to frame it that way.