She found Derick sitting in the car, the door closed. He was leaning back on the seat, eyes closed, and before she came close enough to look in, she knew he was jacking off. His expression told her that even before she was close enough to hear his breathing. Excitement rumbling through her, she slipped quickly to the side of the car and looked into the open window.

Derick had his cock pulled up from the waistband of his trunks, his fist sliding up and down it swiftly. Mandy swallowed as she gazed at her son, watching his fist pumping, seeing the swollen cockhead, his piss hole glistening with seeping pre-cum. The urge to push her hand into the car and grasp his cock was strong, but she resisted. She cupped her cunt as she watched him jacking off, feeling the fiery wetness through the thin cloth of her bikini bottom. She could see her son's balls, and they looked full. Not big, but full. She pressed her hand hard at her cunt, licking her lips hungrily as she watched him.

Derick was gasping heavily, his hips jerking, lifting and falling with his hand. He moaned now and then when he pressed his fist down tight at the base of his cock, the cockhead bulging. Mandy had seen enough cocks ready to come, and it seemed her son was very close to it.

"Uhhhh… ohhhh!" Derick moaned as he jacked off.

Mandy swallowed hard, her eyes blazing as she watched. She was pressing hard at her cunt, her palm moving back and forth slightly as she had done with her brother long ago, only nakedly.

Then, before she expected it, her son came.

The thick cock cream squirted from his piss hole, high into the air.

"Ahhhhhh!" Derick whimpered, gushing hard.

Mandy didn't think, giving in to the strong urge.

Her hand darted through the window, her palm covering the head of her son's cumspewing cock. Derick's eyes flew open.

"Mom!" he gasped.

Mandy giggled, feeling her son's warm cum spurt into her palm as her fingers slid down the hard, throbbing cockshaft.