Do you think this Mistress is pleasuring her male slave? She isn’t.
Sure the bound and helpless man is enjoying her fingers massaging his penis. But only while it lasts.
Before her slave can have an orgasm Mistress moves her hand away. The she goes away, leaving him in the special agony of of the desperately sexual frustrated male.
Later his Mistress returns and uses her fingers to arouse him. And without release. This is how they spend every Sunday afternoon.
When she bores of the cock tease she uses a needle to deflate his erection. One goes his chastity belt.
Mistress has told her slave that is he is perfect in his submission and worship that she will eventually allow him an orgasm.
But she may be lying.
I think the cock tease is one of the corner stones of FLR, by arousing the male she is showing him how she controls his arousal and then by stopping to leave him unsatisfied yet again enforces her power and hold over him.