性的興奮
Physical sexual stimulation usually consists of touching the genitals or other erogenous zones. Masturbation, erotic massage, sexual intercourse, a handjob or fingering are types of physical sexual stimulation involving the genitals. Sexual arousal is usually triggered through sensitive nerves in these body parts, which cause the release of pleasure-causing chemicals (endorphins) that act as mental rewards to pursue such stimulation. A person may also become sexually aroused by touching another person's genitals or other body parts. The bulbocavernosus reflex is triggered by stimulation of the glans penis or clitoris.