My girlfriend, always eager to please, can't wait to get her hands on my throbbing cock. She starts with a sensual handjob, her small hands barely able to wrap around my shaft. But she's got other plans too. With a naughty grin, she positions herself, knees ready. I know what's coming. She slams her knee into my balls, hard. I groan, a mix of pain and pleasure surging through me. She keeps going, alternating between gentle strokes and brutal kicks, until I can't hold back any longer, unleashing a torrent of cum all over her kneeling form.