i know this question sounds inappropiate but im 20 years old and i do masturbate often, but I don't always do it with my hand in a circle, i sometimes lay my penis flat on my pelvis and rub it hard with the palm of my hand, im afraid it's dangerous or damaging, but i havent noticed any decreased drive or abnormalities, if i continue to do it in this weird way is it dangerous? it's a serious question