(A/N: sorry about the length and how scruffy it is but it's mainly here for background and explanation.)
Deku was on his way to class. He had his favourite class after homeroom; hero training! He loved training to be a better hero but everyone thought that he just really wanted to be a great hero and disregarded any chance of a second reason. If people noticed the signs they would still be put to his intense want to be like Allmight. The truth was that he liked it for another reason.
He was gay and most of the class could tell. This excluded Ururaka because she was self absorbed and wanted him for herself. (Sorry to anyone who likes her but she was best for this position and it is needed later on.) Izuku clearly tried harder against the males especially two in particular. Again this was put down to kindness, which while he was terribly kind, was not the reason. The two he tried the hardest against were Bakugou and Shinsou. This may seem counterintuitive as he had a crush on the two of them but there was an unexpected answer as to why this was. If he tried harder then they would too. He had both a strength kink and was a minor masochist. This means that he wanted them to use all their strength against him.
Bakugou was Izuku's first fight. He sat in the back impatiently waiting for homeroom to end. As soon as they were let out he sprinted down to the change rooms to change but slowed once he thought of the possible glimpse of two sets of spectacular abdominal muscles. The rest of the boys joined and Izuku got the view he had wished for.
He knew that many liked Bakugou in theory but wouldn't date him due to his personality. Shinsou on the other hand was liked by a lot especially due to the fact that he took Mineta's place after he was expelled. Because of this he didn't think he had a chance with either but he still liked working with them at least.
After he finished Deku walked out and was quickly clung onto by the one and only Ururaka. He internally sighed but only smiled at her. They got the classic run through from Allmight and Izuku was literally bobbing on his toes in excitement.
They started fighting and he acted overly nice before to get Bakugou riled up. As he fought he made sure to get Katsuki to be as aggressive as possible. This included using the childish childhood nickname 'kacchan' and encouraging him and saying 'better luck next time' any time he missed. This worked and in turn made him use the excessive amount of strength that was at his disposal.
After a couple of other fights he knew he had Shinsou. He rested and ended the other ones quickly. Jirou, Kirishima and Tsuyu weren't much of a competition. Plus he took some anger out on Kirishima as he was 98% sure that he had a crush on Bakugou.
Finally it was his fight with Shinsou. Shinsou may not have been very physically strong to begin with but even then Izuku had a crush on him. He liked him then because he was able to keep Izuku still without having to touch him. He was able to break from it only due to the fact that he was the most bratty sub in existence and he was pretty sure that Shinsou had been going easy.
Nowadays Shinsou had built a ridiculous amount of muscle, not as much as Bakugou but still a LOT. That was evident in his fight. Izuku was working on his muscle as a quiet challenge against the other two.
Izuku fought with Shinsou, trying to make him mad or agitated but the boy was too calm. This always seemed to be the case so Izuku did the same thing as always. He managed to get Shinsou on his back and kept him down. Shinsou clearly didn't like being dominated so he pushed Izuku off to switch their positions. Izuku struggled even though he very much liked it. After a while he gave in and tapped out.
That was yet another day to remember as 'the day Izuku was a bratty sub in training without the knowledge of anyone else'. (Skimming this later to remember the plot and it reminds me of Captain Jack Sparrow. Help💀)
He had liked the two boys ever since he had known them. This didn't include the break in which the bullying got emotional but he liked him through the physical as he could deal with that.
He had regained a somewhat friendship with Katsuki and Shinsou had come as a pair package with him which was awfully convenient for Deku. They hang out occasionally but mostly it's with the bakusquad.
