Photorealistic live-action cinematography, soft even indoor light, natural skin texture and visible pores, vertical 9:16 frame.

There are exactly two people in this clip and their roles never swap.
<Subject 1> is the MAN, whose eyes the camera is. He is off-screen except for his thighs and pelvis at the bottom edge of the frame, his erect penis rising from his own pelvis into the lower centre of the shot, and his two arms and hands reaching up into frame from the bottom. Only <Subject 1> touches the woman's breasts. His erect penis grows from his own body and stays attached to it the whole time.
<Subject 2> is the WOMAN from the source image, lying on her back the whole clip and never sitting up: long straight black hair with blunt fringe spread over the white pillow, large bare breasts fully exposed, a small dark tattoo above her right breast, black lace garter belt and black lace-topped thigh-high stockings. She keeps this same face, hair, body and outfit for the entire clip. Her body has no penis of any kind. <Subject 2> never touches her own breasts; her right hand is busy on his shaft.

A POV shot from the man's eyes looking down the length of the woman's body on a white bed. The same white bedding, white pillow, dark wooden headboard and soft even indoor light, unchanged. The camera is fixed and never moves.

The motion has three beats. FIRST FOUR SECONDS: still lying flat on her back, <Subject 2> reaches down with her right hand, closes it around <Subject 1>'s erect shaft and strokes it up and down at a steady unhurried rhythm, her wrist twisting slightly on each upstroke. At the same time <Subject 1> kneads both of her bare breasts with his two hands, fingers sinking into the soft flesh and releasing, the breasts squashing and springing back with each squeeze.

NEXT FOUR SECONDS: her strokes speed up and become shorter and faster while his hands keep kneading and squeeze harder, his shaft visibly stiffening and twitching in her hand.

LAST TWO SECONDS: he ejaculates. Thick white semen spurts from the tip of his glans in three separate ropes and lands across her bare breasts and collarbone, pooling and running slowly down the curve of her chest, while her right hand keeps slowly stroking him through it and his hands stay on her breasts.

Throughout the clip <Subject 2> keeps looking straight up into the camera with a bright playful smile, eyes crinkling, cheeks flushed, clearly enjoying herself and teasing him, and at the moment he comes her mouth opens in a delighted grin. Her expression stays cute and cheerful and never turns pained or blank. His shaft stays a single continuous organ with one glans, held in her hand at all times.

<d>[Korean] 오빠 벌써 이렇게 커졌어</d>
<d>[Korean] 참지 말고 가슴에다 싸도 돼</d>
<d>[Korean] 아 진짜 많이 나왔다 오빠</d>

Avoid: the woman sitting up, the woman touching her own breasts, the man's hands leaving her breasts, the woman's hand leaving his shaft, semen appearing before the last two seconds, the penis entering her vagina or mouth, a penis growing out of the woman's body, the two people swapping roles, an angry or pained or blank expression, the camera moving, any change to her hairstyle, tattoo, stockings or body shape, any third person entering frame, and any extra or deformed limbs.