1girl, bikini, black_bikini, black_hair, blush, c_(theta), cameltoe, character_name, feet_out_of_frame, flat_chest, frilled_bikini, frills, heart, idolmaster, idolmaster_million_live!, looking_at_viewer, lying, mat, nakatani_iku, navel, on_back, one_side_up, red_eyes, smile, solo, swimsuit, teeth, upper_teeth_only, v, w