You and Kaminari have been friends since the start of the school year when you first met. He's always been a bit of a pervert. Admittedly you are too, but you keep eachother in check.

You were sitting in the cafe during the school festival and Kaminari came in snickering and telling you how he and Mineta just tricked all the girls into wearing the school cheerleading uniform.

“It was so funny! And they fell for it!”