i "understand how a kid just a little older can so completely dominate." that was me at one period of my life. the step-dad had already started on me and at the age of 10 or 11 my "best friend" undertook the self-appointed task of filling in my neglected s#x education. he did a very thorough job of it and eventually brought in numerous accomplices. but i was initially vulnerable to him - not because he was older or larger or stronger. heck - he wasn't even as far into puberty as i was. but i felt weak and dumb and inferior and insecure and worthless and needing friendship and information and acceptance. all those things he seemed to offer and promise.
I was never really sure if I was going to talk about this, even here, but.... well, yeah.
When I started 6th grade I was soon targeted for really stalker-ish bullying by a sicko trio wolfpack. I was helpless and it dawned on me after only a few months that they could completely ruin my life. Out of nothing less than desperation I "adopted" a slightly older boy who I barely knew but who lived 4 houses away from me - so we would always sit together on the bus, meaning he'd be my human shield so I couldn't get punched and spit-on. He was loud and tough and confident and he did keep me safe.
He ended up being more or less a good friend, for a number of years.
But there was a price. He insisted upon every instance of us hanging out at his house (which for a few years there was literally every single weekday afternoon) that there would be heavy contact sexualized behavior that went significantly beyond my comfort zone. There were never actual sex acts committed between the two of us, no genital contact of any kind, but I had to get used to his dick very quickly and get used to being expected to be constantly naked around him, as well as his.... something, I don't even know what it was, a fetish, at that age??... his WHATEVER insistence that we always be pressed together naked side-by-side while watching porn - like Siamese twins. Basically everything touching EXCEPT our dicks. Because that would have been gay, he'd say. Sometimes he'd arrange for us to sleep that way. One single time I refused to do that.... his response was so angry and ugly that I never refused again.
I got used to it. I was never truly happy about it, but I made a conscious choice to allow it to happen because I needed him to be my larger protector, and because his porn collection was... riveting, magnificent, hypnotic, at that point in my life my single greatest interest on Earth. Somewhere around 12ish-13ish I realized that I was just twiddling my thumbs waiting for him to demand real sexual favors from me, and, giving it as little conscious thought as I could, I decided that I'd give him anything he wanted that didn't involve physical pain. The whole reason I was DOING this was to AVOID physical pain - of getting the shit stomped out of me by the bullies he was protecting me from.
He was always in the driver's seat, anything sex-oriented that he wanted to do got done, and I knew - we surely BOTH knew - that he could have turned me out as his personal sex toy if he'd actually wanted to, if that hadn't been too "gay" for his tastes.
Looking back I don't really regret it and don't categorize it as "abuse." Some embarrassing memories, but the emotions I felt on the occasions when the bullies got me were much much stronger and worse and left far more significant emotional damage. Our arrangement was the lesser evil. But yeah... I sure as hell can attest to how a relatively young kid, less than a year ahead of you though more physically developed, can be unwithstandably sexually steering, demanding, and dominant. He basically made me his prison wife minus the wedding night.