My story is very similar to the OP's. I had posted (a version of this) on Allkink years ago as well.
True story that sounds made up, but whatever. My first legal "jock sex/fuck' was my Football coach, on my 18th Birthday. He and I talked about Football, our love of the “athletes life” as well as life in general for three years in H.S. I (thought I) never let on that I had the hots for him, and to his credit, he never did more than coach and tolerate me and my dumb questions either until I reached legal age. We did share a mutual love for bodybuilding as well as a quest for finding the perfect jockstraps, either with a cup (I was Defensive Line, so I wore one) or without. I know i brought up Jockstraps to him so many times that I should write my Senior paper about them (I didn't, for the record)
For my 18 birthday, he took me to his house for the first time and gave me two new Jockstraps, a Bike #10 Pro model, and a Bike #58 Cup and Jock. I asked if it would be okay to put the Pro #10 on, he had no objections. I grew a boner that was the product only an 18 YO could make, straight up in the air.
He said he had a surprise for me back at the Gym, and let me drive his 10 year old Corvette back to school, it was maybe 9pm, on a Saturday night, but he had the keys. In his “inner” office there was a massage table that I watch him fill 2 feet high with used jocks, the product of maybe three years of jocks swiped from the unclaimed lost and found box at the gym.
He and I started to make out, then he put me on the table with the used jocks, I was in heaven. He told me that one of the other coaches saw me swiping two jocks from the benches a few weeks earlier, he told coach Holmes that “he would take care of it”. He put me on the jock filled table, then sucked me off, I repeated what he had just taught me on him. I def was not ready when he asked me to Top him, but with no learning curve, the teenage animal in me took over and I took my first guy anally.
This is controversial, but, I fully believe that "gay and straight" are just points on a line, nothing more and should have never been a big deal until who knows who made it so. No one outside of my gay friends knows I’m "gay", My "straight" friends have always just assumed I'm "straight". I love the smell, size and the brain of masculine and absurdly masculine men, but I have had great sex with twinks and effeminate men as well. My sex life has included guys and women and at least one trans. and, oh yeah, more that a few "straight" guys, as any man who has sex with other men knows very well.