Sexual intercourse (or coitus or copulation) is principally the insertion and thrusting of the penis, usually when erect, into the vagina for sexual pleasure, reproduction, or both.[1] This is also known as vaginal intercourse or vaginal sex.[2][3] Other forms of penetrative sexual intercourse include anal sex (penetration of the anus by the penis), oral sex (penetration of the mouth by the penis or oral penetration of the female genitalia), fingering (sexual penetration by the fingers), and penetration by use of a dildo (especially a strap-on dildo).[4][5][6] These activities involve physical intimacy between two or more individuals and are usually used among humans solely for physical or emotional pleasure and can contribute to human bonding.[4][7]