Dude, they're like 14/15 years olds, give the boy a break haha.
You may not remember but you surely had those little pervy moments aswell...
I think the author did an amazing job portraying a young boy on his first experiences, similar mangas with MCs of the same age always fail at that, they all feel more like guys in their 20s/30s than adolescents in full puberty mode.