I do like the moments in Nudist Beach ni Shuugaku Ryokou de where women just hang out on the nude beach. Not even necessary doing anything sexual. Sadly it not happens often, but I guess you just have to complain about wasted potential when mentioning this manga.
The setup and early interactions were gold
If there hadn't been a fuck tent or no erection rule at least some of the boys could have popped boners as soon as the teacher came out
The nude reveals could have been extended a bit too in hindsight, first chapter is crammed