2girls, bad_pixiv_id, bead_necklace, beads, blue_hair, breasts, bubble, gem, idolmaster, idolmaster_(classic), jewelry, kiria_ai, kneeless_mermaid, large_breasts, long_hair, looking_at_viewer, mermaid, miura_azusa, monster_girl, monsterification, multiple_girls, musical_note, navel, necklace, shell, shell_bikini, shijou_takane, short_hair, smile, sparkle, underwater