A dildo is a sex toy. It is most often used in place of an actual penis for sexual reasons. Dildos come in many different shapes, sizes, and materials (most often glass, plastic, rubber, metal, or wood) for different looks and feels, different uses, and to provide the best stimulation for different people. Some dildos vibrate and pivot for extra pleasure.
Both men and women can use dildos. They are most often put into the vagina or anus, but are sometimes used in oral sex. Since dildos are very simple toys, they can be used in many different ways. They can produce arousal to the point of an orgasm. For this reason, dildos are commonly used for masturbation.