This happened in school (more like junior college). Before y’all go all judgy on me, we were on or above the age of consent, it was consensual and there was no sex technically.
Our school had a habit of seperating boys and girls in seperate classes. That was only upto a certain grade and suddenly poof boys and girls were in the same class.
So we were seated in tables of 3, being in the last table in the corner, myself and my friend Ben (Uncle Ben we called him, not just a spiderman reference but was literally quite big for his age, like literally he was huge) we were just a normal couple of friends who grew up together.
That was until Ben discovered porn and things got weird between us.
I realised later that we discovered porn much later than a average human does but that didn’t stop him. From that point on, every teacher or girl classmate he saw, he made a comment about boob size, butt etc and then he started guessing about dick sizes of guys (well he swung both ways, should have guessed)