Unknown 9: Italian coming-of-age drama 1980s 90s

I'm searching for another, probably Italian movie, maybe coming-of-age film. Filmed and set in the (late ?) 1980s or early 90s?

I only remember this scene. 2 darkhaired boys, around 13. They are on flat stone steps or staircase on a hill at a typical seaside setting with white stones. And maybe a stone wall on the background.

The left boy is cool (showoff) and said he has a girl or did it or something like that. The right boy don't believe it and said you don't even have pubic hair. Without hesitation the left boy dropped his shorts (maybe dark, brown or grey or dark blue, not bright color) in one turn to the ground and I think lift up his shirt a little to show that he has. No details shown. The other boy isn't much impressed.

Maybe later swimming scenes with some boys at a harbour or beach with cliffs, view from top.

I checked about 10 or 20 movies that looked liked this setting but haven't found it yet. I try to find some better pics ressembling this scene.

Update: I still haven't found it 2 months later. But I made a better pic and listing similar movies which I have checked completetly or partly.

/2015/08/07/update-of-unknown-9/

Update 2: I bought "La Storia" but it isn't it. I now found a screenshot

/2016/12/01/unknown-9-pic-found/

Update 3: Better pic, higher resolution

/2017/01/24/unknown-23-french-update-unknown-9-italian/