Gaku didn't say it was to take revenge for middle school. He said, "I started teaching you about sex as a diversion because I was so angry over being teased during middle school". Ok, so we know a couple of things about Gaku 1) he only had sex with his senpai, dated a lot of girls but never went all the way 2) he always had a feeling of discomfort when dating girls 3) he was isolated due to the rumors and teasing in middle school 4) he transferred schools to get away from girls asking him out and to get away from said rumors!
So he attends an all-boys school, meets Himari, they hit off really well. They both agree that coming to school is fun because of each other. Later, some classmate brought up Gaku's "playboy" days and even said "has your crotch calmed down a bit?". Ofc that pissed him off and Himari could tell. I'm guessing he wasn't really thinking too much when he suggested to teach Himari how to fap. As he said, he needed a diversion. So maybe partly out of spite, partly out of curiosity, and maybe even a subtle attraction to Himari, he proposes to teach him how to masturbate. I think Gaku enjoyed it as much as Himari did (he kept calling Himari cute uwu). It's because of this he gradually realized he's more into men than women.
Personally, I think it's one of those things teens just do. I'm not saying a lot of them fap each other off but I'm sure there are a couple of guys out there who got curious and decided to jack off together in an all-boys dormitory. They're in their teenage years. It's a period where hormones are running high and they're slowly discovering their sexual preferences/identity. In ch2, Gaku questioned himself what the hell he's doing cuz they both know that friends don't normally do this.
I think we got used to the common BL trope of semes blackmailing/coercing innocent ukes into doing sexual things so we expected the worst out of Gaku. In a sense, Gaku did take advantage of Himari but we all know Himari is the straightforward type. If he wanted this to stop, you bet your ass he'd tell Gaku.
Let's not forget that Gaku never pushed Himari if he didn't want it. "I refused his offer. It doesn't matter what I answer, he'll always follow with an 'I see'. He's never said, 'I can't today' or 'I want you to come today'." - Himari ^q^
very well constructed response, very nice!
Thank you! (๑•ㅂ•)و✧ I just wish OP would answer back when I replied with the requested explanation they wanted, haha. I'm glad it was Gaku who found Himari. He was very patient and didn't push him to do anything he didn't want. Any other BL seme would've probably sexually coerce Himari, humiliate him for not knowing what fapping is, and threaten to tell everyone in school.
Can someone explain to me why Gaku started playing doctor with himari ? I really do not understand his motivations. What does being ostracized in middle school has to do with touching your friend's peepee (as he says "sorry i was trying to take revenge for middle school")?