Not sure, but I had a situations hearing the boys watching porn together and sometimes lending a heand to a friend. So maybe they do lol.
But in this situation I think the MC's fried kinda like him, because of how disappointed he was when MC said it wasn't that important of an event etc. And MC is about to find out he isn't straight either.
It's been in so many mangas (sorry if that is incorrect) I'm genuinely curious as well.
you can see a whole discourse of it in reddit, but i couldnt access it since i didnt have an account.
"normal" might be a stretch but it definitely happens
I do this often in my volleyball club whenever we changed clothes
Genuinely curious as to whether it is normal for "straight boys" to jack each other off