HELLO! I am 13 yrs and recently I realized that I should pull back my foreskin to clean my penis. The question is, there is this faint layer of cheesy thing that will not get washed off under running water and even when I use hands to gently caress it, it does not come off. Should I use my hands to wash my penis or should I just run it under warm water? It feels sensitive when I touch it... Help please...