Bakunyuu! Dekajiri! Ama Oba-san

Shinichi Hayasaka paid a visit to his aunt Mariko's home, where he had lived as a child.
She was like a mother to him. However, she had become a diver in the years he was away, and he saw her now in all her womanliness: mature, alluring, incredibly sexual.

[From DLsite English]