The clitoris is a female genital organ. It includes erectile tissue, glands, muscles and ligaments, nerves, and blood vessels. Although the parts are placed differently, the clitoris is a match to the male penis. The clitoris causes female sexual pleasure, arousal and orgasm. Rubbing or applying other consistent pressure to it is usually needed to help the female have an orgasm. During sexual arousal, erectile tissue fills with blood. This causes the clitoris to grow. It grows until orgasm happens. Also during arousal, touching the clitoris and other sensitive areas of the female genitals makes a woman's vagina change shape and release a lubricant. The lubricant and change of shape makes it easier for a man to enter a woman and for sex to occur. Most of the clitoris is hidden inside the body. Only a small part of it is seen outside the body. Adding the outside and inside parts, the clitoris about the same size as the penis. The clitoris and penis grow from the same tissue in the womb; they bare many similar parts.