Explain masturbation and the object of it.?

Erotic pleasure. The object of masturbation is to experience the sensation of erotic pleasure in the penis or the clitoris. Masturbation is performed by rubbing or stroking ones own penis or clitoris, or doing the same to another person. Such stroking or rubbing can lead to orgasm. In males can result in ejaculation, in females to sudden release of an intense pleasurable sensation. It can be enhanced by videos etc.
Play with genitals. Masturbation is playing with genitals, either one's own and/or those of an appropriate partner. It is just another one of those amazing activities that humans are able to do, such as singing, dancing, swimming, etc... The objective is usually just fun, but there can be other goals, such as relieving tension, helping with insomnia, checking the success of a vasectomy, being a sperm donor, etc...