Poor Kim! I'd heard the confession in the kitchen. Kim had failed Calculus II in her engineering program. Peeking around the corner I'd watched Kim's mom explain that although she was twenty, because she lived under her parent's roof, it was their rules. Either she got straight B's and A's or she got discipline. Then Ms. Jerrod  proceeded to have her terrible way with a hefty wooden spoon on Kim's poor, poor bottom. Kim's eyes glazed over and she yelped heartily as she got owned.
I tiptoed into her room afterward. Kim was on the bed with her reddened bottom cooling in the evening breeze. My erection sprang immediately. Those gorgeous globes had been beaten tomato red  Beside her was the report card - but it was straight A's. I didn't understand... but then I did. Kim wanted the beating.  I furiously pulled my clothes off then tenderly put my hand on Kim, stroking her hair, her back, and finally, gently, her ravaged bottom. She sighed and moaned.  I couldn't wait. Fingers shaking, I rolled on a rubber, and then guided my cock to her waiting vagina. She reached back and pulled me inside, groaning, as my head pushed its way through her tight wetness.
As I gloriously stroked in and out, I placed my hand on those sensitive, punished globes. I didn't know how long I could wait. Fortunately I didn't need to. I felt Kim's shuddering climax before I poured myself into her.