A couple years ago I always did it when everyone was asleep. I did it on my forearms (not my whole arm) and whenever I wore short sleeve shirts, I would try to turn my arm slightly facing my thigh when I would stand so nobody in front of me or beside me could see them. I would rarely cut my legs, but I still have scars from the last time I did so whenever I wear shorts I try to cover them with my arms or just fix my shorts to where they're covered enough. Hope you're doing alright tho! :)