1girl, armpits, arms_behind_head, breasts, competition_swimsuit, fang, greyscale, hair_ornament, hairclip, hand_in_own_hair, head_cha_la, ijiranaide_nagatoro-san, long_hair, medium_breasts, monochrome, nagatoro_hayase, one-piece_swimsuit, open_mouth, smile, solo, sweat, sweatdrop, swimsuit, white_background