The Usual refers to a persons "Go To" move used as a prelude to sex/love-making.
Jon: Sweetie, can I give you a backrub to help you fall asleep?
Karen: Ah... The Usual? Sure that would be nice
Jon then proceeds to rub and kiss Karen's back and then her bumb until he is ultimately making love to her.
Karen: That's not my back Jon...but keep going...