4girls, >_<, aki_(girls_und_panzer), back, blue_eyes, blunt_bangs, breasts, brown_eyes, brown_hair, closed_mouth, girls_und_panzer, holding, holding_instrument, indoors, instrument, kantele, light_brown_hair, long_hair, looking_at_viewer, looking_back, low_twintails, mika_(girls_und_panzer), mikko_(girls_und_panzer), multiple_girls, music, nabeyu, naked_towel, open_mouth, parted_lips, playing_instrument, red_hair, sauna, short_hair, short_twintails, sitting, smile, towel, traditional_media, twintails, wet, wet_hair, white_hair, white_towel, youko_(girls_und_panzer)