The pain of the small cage and a plug that was 2 sizes bigger than you were used to was almost too much, but the pure pleasure you were feeling from the rush of arousal was enough to keep you going forward with your training.
You're mistress knew all she ever had to do was talk about touching you and you would get hard and feel the endless frustration of the cage, however, on certain days she would take down your panties and rub herself against you cage. It was almost enough