takafumi, original, absurdres, highres, 1boy, 1girl, age difference, black hair, blue eyes, blue one-piece swimsuit, blue swim briefs, breasts, brother and sister, bulge, competition swimsuit, covered navel, cowboy shot, hand on another's shoulder, highleg, highleg one-piece swimsuit, indoors, lane line, male swimwear, medium breasts, navel, one-piece swimsuit, onee-shota, parted bangs, ponytail, pool, siblings, smile, swimsuit