The dream always starts the same: Miss Grant not with you today, Doctor?
I'd rather we have some time alone, if you don't mind, old chap.
Not at all, he says, and falls into the Doctor's embrace, his kiss.
Sometimes the Doctor is tender, sometimes he's demanding. The act itself varies; in their youth, they discovered a myriad of ways to satisfy each other. Though he's spent centuries trying to forget, his body remembers.
The conclusion is the same, though; the Master wakes alone in his luxurious cell, in need of a shower, with a hollow feeling between his hearts.