The slave is on a gymnastic-ball and makes a good toy for Rosie's desires.
She steps over him and drops down on his chest, her impact causes a loud blow-out from his lungs.
Once safe on the chest, she begins to make riding-moves and bouncing with heavy landings on his chest.
Then she turns around, drops again on him and begins to move back with every bounce a little bit closer to the throat... windpipe-riding follows.
To the end, she lands finally on his face, the nose goes where it has to go..... deep in her ass ;-))))