You sent the key to your chastity belt to your mistress as a mark of trust? You failed bad. What did you think would she do with it? You're completely at her mercy now and have to follow her direction, fulfill every single command - no matter if you want it or not, you HAVE to! Except you don't want to see your tiny, useless dick ever again.. she will tease you 'til your brain is fucked up and lost beyond recall!
I know you have a very small penis, bet that's no excuse. You still have to learn chastity control like the rest of them. I could try to put a normal size chastity belt on you, but what's the point. You would slip right out of it. Then you would be off jerking off as much as possible. I found a small solution to keep you caged and chaste like the rest.