When this mistress realized she had been played by her boyfriend, she knew it was time to make him realize she was not one to mess with and hope that he will get away with it. So the mistress cruelly kicked him in the nuts and when she was done, she slapped the crap out of him. He never made that mistake again and he learned his lesson the painful way.
Mistress Nikky wanted to find out how tough her slave was. She tied him to a cross while he was naked. She did so in order to render him helpless. She had him all to herself now and she beat him up cruelly. She wanted test his breaking point so she did all sorts of things including slapping him as brutally as possible and leaving him with a red face.