In general, masturbation within a normal and moderate frequency can be considered a normal part of sexual development for boys. It can help relieve sexual tension. However, excessive masturbation may lead to some problems such as fatigue and reduced concentration.
Yes, it is often normal. Masturbation is a common sexual behavior among boys during puberty. It is a way for them to explore their own bodies and sexual feelings. But it should be done in a private and hygienic environment, and not become an obsessive - compulsive behavior.
For most boys, masturbation in moderation is not harmful. It is a natural expression of sexual development. However, if it starts to interfere with daily life, like causing problems in school or social relationships due to excessive focus on it, then it might be a concern. Also, good personal hygiene should be maintained during this process.