1girl, bare_legs, barefoot, black_hair, blue_bra, blue_panties, blush, bra, breasts, cellphone, cleavage, content_rating, cover, cover_page, curvy, doujin_cover, feet, full_body, glasses, green_eyes, hair_between_eyes, holding, holding_phone, huge_breasts, i_can't_handle_my_former_bookworm_little_sister_now_that_she's_a_slut!, kneeling, long_hair, looking_at_viewer, natsuki_(bookworm_little_sister), open_mouth, original, panties, phone, smartphone, smile, solo, teeth, thighs, toes, tsukumiya_amane, underwear, underwear_only, upper_teeth_only