You are 16 years old this year. Your penis is still developing. So there is no need to use any promotion means.

Because it's not just unnecessary. More unnecessary! On the contrary, it will harm its natural growth!

You masturbate. It doesn't matter as long as the frequency is not frequent.

And 10 cm is not bad. Please don't worry! Not small. It will grow in the future!

Of course, your age is easy to increase. But you don't need it now.

The penis will naturally grow and harden. What you need to do now is to masturbate less. Eat more food and exercise more.