happyundergate, oyama mahiro, onii-chan wa oshimai!, commentary, highres, 1boy, 1girl, :d, ahoge, bare arms, black skirt, blush, bra, bra peek, brown eyes, brown hair, button gap, colored inner hair, desk, ear blush, faceless, faceless male, flat chest, grey hair, leaning forward, long hair, looking at another, multicolored hair, neck ribbon, open mouth, pink background, pink hair, pleated skirt, red ribbon, ribbon, school desk, school uniform, shirt, short sleeves, simple background, skirt, smile, suspender skirt, suspenders, sweatdrop, two-tone hair, underwear, white shirt, wing collar