Making a person's penis go limp, without achieving orgasm.
To deny one's submissive person to have an orgasm, to deliberately bring about their loss of an erection, despite their craving, need for ejaculation.
This is a form of teasing, as well as to help build the excitement up, as well as to show one's dominance or control over another.
Noteworthy: The most common method used, to create this sexual frustration, is to apply ice cubes to the groin, penis. The cold automatically creates a shrinking response.