Woman on top, also called the cowgirl or riding position, is a group of sex positions in which the man lies on his back or sits, the woman straddles him facing either forward or back, and the man inserts his erect penis into the woman's vagina or anus.
The cowgirl name derives from the image of the receiving partner "riding" the partner as a cowgirl rides a bucking horse. It is one of a number of receptive-partner-superior sexual positions, another being the reverse cowgirl position. It is fairly simple to achieve and maintain and pleasures both partners. This position is also used as a precursor to the lateral coital position described by Masters and Johnson.
This position is commonly cited as one of the more popular sex positions, especially by women, because of its ability to adequately stimulate the clitoris. In this position, the woman is usually the active partner during the sexual activity.
In the cowgirl position, the man lies on his back or sits, with the woman straddling him across his pelvis facing forward, either in a kneeling or squatting position. The woman will align her vagina with the man's erect penis, and lower herself onto the penis with either the man or the woman guiding the penis into the woman's vagina for penetration. With the erect penis inside the woman, the woman can glide up and down the man's penis, controlling the rhythm and pace of vaginal stimulation and the extent and duration of penetration. The woman is free to change her position ranging from leaning back to stretching out on her partner's chest to rocking from side to side or in a circular motion. Each of those changes would alter the angle and depth of penetration and which part of the vaginal area and sex organs are stimulated. The man's hands are free to reach and touch the woman's breasts, clitoris, buttocks, face etc., and the partners can maintain eye contact. With the woman in the sitting or leaning back positions, the man may also stimulate her nipples and clitoris with his fingers, or suck on her nipples if she inclines towards him or he raises his torso towards her.