have an exercism?
pray.
the butts are attached to real people so as long as you recognize that and you don't act out and do bad disrespectful things to those girls, and don't porn monger, and don't fetishize it and put it above your love for God then I'd say what you do is get one look, then look away and then love the person who it is and don't ruin your chance to be a normal person in that person's life by being a creep to them.
if it's really young people that you're interested what you should do is move somewhere that is far enough away from them that you will never ever ever be tempted like that.
what do you do?
grow up