gan-chan (artist), narushima ai, discovery software, tsuma x tsuma 4, game cg, 1girl, backstroke, black one-piece swimsuit, blue eyes, breasts, brown hair, competition swimsuit, covered erect nipples, dutch angle, female focus, from above, impossible clothes, impossible swimsuit, jewelry, lane line, large breasts, lipstick, long hair, looking at viewer, makeup, one-piece swimsuit, open mouth, pool, ring, solo, swimming, swimsuit, water, wet