Tease and denial (also called "orgasm denial" or "T&D") is a general term used to describe any technique that involves the sexual stimulation of a person to cause intense arousal without climax. It is usually practiced for the express purpose of creating powerful feelings of sexual frustration and pleasure in the person being stimulated by singly or repeatedly bringing the subject to the brink of orgasm without actually causing orgasm.
Bringing someone to the "edge" (or brink) of orgasm is called "edging". Edging in addition to prolonged sexual excitement or stimulation will frequently produce pre-ejaculate or "precum". This can be seen as a sign that effective teasing of the male has been applied. Blue balls is another signal that teasing and effective denying has taken place.
A series of T&D sessions can sometimes lead to a ruined orgasm. This can be extremely effective in causing sexual frustration in that the person is led to believe that he is about to have the orgasm that he has been consistently denied. Ruining the orgasm only deflates the orgasmic euphoria and it places the person back in the submissive, controlled position in respect to his partner.
How long the tease lasts, the number of sessions until orgasm (if any) and the methods used varies from couple to couple. This practice is associated with BDSM, but can also be used to augment vanilla sex relationships as well.