Sexual frustration
From wipipedia.org
Sexual frustration describes the condition in which a person is in a state of agitation, tension or anxiety due to a quantity of sexual activity and/or sexual satisfaction that is less than required or desired. Or perhaps the state of being deliberately sexually aroused but not allowed to act on the feeling.
A dominant will often use erotic sexual denial or control to create a state of sexual frustration and longing in his or her sub as an element in a scene, or in a 24/7 situation.