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.
Your purpose my slut is simple. You are mine to use and abuse for my pleasure. You are mine to humiliate and degrade. Your purpose is to take whatever your mistress gives you with a smile. Do you understand? Repeat it.