13 year old going through puberty wondering if safe to cum during masterbation?

Yes, is safe and necessary for health.

Masturbation is good because it provides for the need to ejaculate semen, is fun, pleasant, enjoyable, safe, healthy, normal, harmless, contributes to prostate health, relieves sexual tension, and pain from overfilled seminal vesicles. Masturbation aids sleep when done before bedtime. Frequent masturbation prevents wet dreams. Masturbation leaves one with a feeling of relaxation, contentment, and well-being. One cannot get an STD from masturbation.Masturbation should be done in a place where one has privacy. Favorite places are in the shower or in bed at night.

There is no lower or upper age limit for masturbation. Some pre-school boys masturbate and some elderly people masturbate at least into their late seventies.One may masturbate as much or as little as one wishes, however one may experience temporary sexual exhaustion due to very frequent masturbation.