Masturbation is when a person touches their own sex organs to have pleasure. It often results in an orgasm.
Masturbating may be done alone, but can also be done with another person. This is called "mutual masturbation". Vibrators and dildos can be used to make masturbation easier or feel better, but it is often done with just a person's hand. Studies have shown that many people masturbate regularly.
Animals can masturbate too.