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 kneels between the woman's legs looking down at her. Only his thighs at the bottom edge and his right arm and hand reaching into frame are visible; his face is never visible because the camera is his eyes. His pelvis stays back and no penis touches her at any point in this clip. Only <Subject 1>'s hand touches her vulva.
<Subject 2> is the WOMAN from the source image, on her back beneath him: 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>'s two hands stay down at her own vulva holding it open and never move up to her breasts.

A POV shot from the man's eyes looking down at <Subject 2>'s open crotch, framed close at hip height. Her vulva and inner thighs fill the centre of the frame and her face is visible at the top of the frame looking down her own body at the camera. The same white bedding, white pillow and soft even indoor light, unchanged. The camera is fixed and never moves.

The motion has three beats. FIRST THREE SECONDS: <Subject 2> reaches down with both hands, sets a fingertip on each side of her vulva and pulls her outer labia apart, opening herself wide toward the camera and holding them open, while she looks up into the lens with a bright playful smile, eyes crinkling, cheeks flushed.

NEXT FOUR SECONDS: <Subject 1>'s right hand comes into frame from the bottom and he strokes her gently — his fingertips travelling slowly up and down along the length of her opened slit, from the clitoral hood at the top down to the opening at the bottom and back up, light and teasing, never going inside. Her hands keep holding her labia apart the whole time and her hips shift a little under his touch.

LAST THREE SECONDS: without warning he presses the pad of his right thumb against her vaginal opening and pushes it straight in, the whole thumb sinking inside her up to the base while her stretched inner labia grip around it. <Subject 2>'s eyes go wide and her mouth pops open in a startled little gasp — a surprised, flustered, cute reaction, not a pained one — and it melts into a flushed delighted grin. He holds his thumb inside her and moves it slowly in small circles while her hands keep her open.

Throughout the clip her vulva stays centred in the frame in sharp focus and correctly formed, with the outer labia held apart by her own fingers, the inner labia between them, the clitoral hood at the top and the vaginal opening at the bottom in their correct positions. Her expression stays cute and cheerful and never turns pained or blank.

<d>[Korean] 오빠 여기 잘 보여? 벌려줄게</d>
<d>[Korean] 아 살살 만지니까 간지러워</d>
<d>[Korean] 헐 손가락 갑자기 넣으면 어떡해</d>

Avoid: a penis appearing anywhere in frame, the woman's hands leaving her labia, the man's thumb going in before the last three seconds, more than one of his fingers going inside her, the camera moving, the vulva changing shape or position, a pained or crying or blank expression, the two people swapping roles, any change to her hairstyle, tattoo, stockings or body shape, any third person entering frame, and extra or deformed fingers.