It gets bigger and bigger

After the Sissy has cleaned the Mistress's house well, there is now a reward, a brand new strapon. And it gets bigger and bigger, as the Sissy realises to her shock. Out of sheer fear she whines and begs the Mistress that it is much too big for her tight asshole, but all she manages to do is get the whip on her rubber ass and then the asshole is made to fit the extra large intruder.