The slave is bound to the bench in the dungeon and the mistress feels like pushing his boundaries. Now with sounding your either love it or hate it - will this slave love it? Mistress uses her sounding equipment to get the urethra warmed up and stretched. As She inserts the probes into the hole the slave squirms. Eventually, Mistress decides to test the slave - by inserting her pinky finger into his opening, stretching and teasing the urethra - how far will she be able to push her finger into his canal?