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 sits back with his legs open toward her. Only his thighs at the bottom edge of the frame, his pelvis and his erect penis standing up in the lower centre of the shot are visible; his face and hands are never visible because the camera is his eyes. His erect penis grows from his own pelvis and stays attached to his body for the whole clip, a single continuous organ with one glans.
<Subject 2> is the WOMAN from the source image, sitting facing the camera with her legs open around his: long straight black hair with a blunt fringe, very large bare breasts, a black lace bra pushed down beneath them, a black lace garter belt and black lace-topped thigh-high stockings. She keeps this same face, hair, body and outfit for the entire clip and never turns into anyone else. Her body has no penis of any kind.

The same beige wall, wooden trim and grey woven mat as the source image, unchanged. The camera is fixed and never moves. The room is quiet: a soft room tone, the rustle of skin and the wet sounds of her mouth.

The motion is one continuous action for the whole clip. <Subject 2> leans forward, presses her two heavy bare breasts together around <Subject 1>'s upright shaft with a hand on the outside of each breast, and slides her chest slowly up and down along it, the soft flesh dragging over the shaft, again and again without stopping. At the top of every slide the glans emerges from her cleavage; each time it appears she dips her head, closes her lips around the head and sucks it, her cheeks hollowing as she pulls on it, holds it in her mouth for a beat, then lets it slip out with a wet string of saliva and slides her breasts down again. She repeats this rhythm — breasts sliding up, mouth sucking the exposed head, breasts sliding down — for the whole clip and never stops.

Between the sucks <Subject 2> looks straight up into the camera with a bright playful smile, eyes crinkling, cheeks flushed, clearly enjoying herself and teasing him, and while the head is in her mouth she makes wet muffled humming sounds around it. Her expression stays cute and cheerful and never turns pained or blank. His shaft stays held between her breasts at all times, only its head ever entering her mouth.

<d>[Korean] 오빠 이거 가슴에 다 안 들어가</d>
<d>[Korean] 웁… 으읍… 웁…</d>
<d>[Korean] 끝만 빨아줄게 참지 마</d>

Avoid: her breasts leaving the shaft, her hands leaving her breasts, the whole shaft going into her mouth, the penis entering her vagina, a penis growing out of the woman's body, the man's hands appearing in frame, the man's face appearing, the two people swapping roles, an angry or pained or blank expression, the camera moving, any change to her hairstyle, bra, garter belt, stockings or body shape, any third person entering frame, and any extra or deformed limbs.