Thanks for query,
is a common practice in your age group.
It will not affect your body or organ or health.
There is no protocol that you should go for this much masturbation act in a week is good & this much is bad.
You feel desire for it go for it.but at the same time you should remember that excess is always poison.
Sex is in our mind.
if you have thought of sex in mind always you should have desire for it.
Just divert your mind by busy with other activity.
Penis front skin color is due to pigmentation.