プロンプト

A scene capturing the moment a 20-year-old Japanese man masturbates and ejaculates. He has fair, smooth skin and pink nipples: a handsome face that rivals even K-pop stars: stands 177cm tall and weighs 78kg: and possesses a 21cm erect penis with a large glans. As an active swimmer, he has a well-trained, muscular physique, double-lidded jet-black eyes, and short, light-brown hair. He strips naked poolside, grips his massive cock with a large hand, and ejaculates vigorously—spraying semen—during a dynamic masturbation session.