I used to stay at hostel while in college. We used to take long walks inside the hostel campus discussing what not. One summer day, I was doing so with a male classmate. It was hot, we went to the rooftop. We were talking about vaccine or something, and he took his shirt off. It was disgusting. I told him to put it on, of course I very politely and mildly, because, well, I was alone on the roof with him and it didn't feel safe or sane to speak my mind to the guy, and he thought I was embarassed/attracted or something IDK. He laughed and continued staying shirtless. I soon left the place.
Another regular incidence was the hostel boys playing football shirtless in the field. The field was in front of the balconies of the girls' hostel. And, it was annoying, hilarious and disgusting to see them taking their shirts off, especially when a number of our balcony doors were open. They knew girls can see them, and they enjoy the fact. But somehow strangely, it's always the girls who are slut-shamed.