The clitoris you can see and touch is the tip of the iceberg. The full clitoris extends 3 or 4 inches inside the body. It consists of 4 'bulbs' hidden beneath the surface which wrap around the vagina, 2 either side. These bulbs fill with blood and become firm and erect during sex excitement, just like the penis. The clit erection helps the vagina and penis work better together during sex. The bulbs help guide the penis in and out. This is one of the reasons why foreplay is important before sex.