How To Prevent Children From Masturbating?

my 5 year old little sister is masturbating frequently...at school, at home, in the car, it doesn t matter. if she s caught because someone walks into the room, she had no regards for that person and continues to do so. i know it s a normal behavior, but she s already suffering from bladder infection and the consistent rubbing is making her raw. it s something that s been going on for years, but became more frequent when she turned 5. she denies doing it....and has a severe attitude when you try to talk to her about it. aside from talking to a pediatrician, is there anything else we can do? do we need to consider seeing a counselor?