2girls, d, o, bare_arms, bare_legs, bare_shoulders, barefoot, bikini, black_background, black_hair, blue_bikini, c, jdge, long_hair, multicolored_hair, multiple_girls, navel, onii-chan_wa_oshimai!, open_mouth, oyama_mahiro, oyama_mihari, pink_bikini, pink_hair, purple_hair, riding, seashell, shell, siblings, sisters, smile, starfish, swimsuit, twintails, two-tone_hair, water, water_gun, wavy_mouth, yellow_eyes