Tie Me Up, Teacher! 3: F**k for an A

EXCERPT: Behind her she heard the sound of him unzipping his fly, and soon the pressure of his rock-hard rod was pulsing against her. He smacked her ass with his cock, then with his open palm.The sudden spanking startled Kitty, and she gasped in surprise. Her ass stung as he slapped it again... but she'd by lying if she said she wasn't enjoying it. She bit her lip and thrust her ass in the air, "Oh, please spank me more, Professor, sir," she begged in a pleading tone, "I've been such a bad, naughty girl. I need you to punish me and make me be good for you." Her professor instead stopped his abuse of her rear, and soon Kitty was reduced to actual begging, "Professor, please, please spank me more, I've been bad..."