akiyama mio, hirasawa yui, kotobuki tsumugi, tainaka ritsu, k-on!, absurdres, highres, 4girls, arms behind back, bdsm, blush, bondage, bound, bound ankles, bound arms, bound legs, box tie, breast bondage, breasts, chair, gag, gagged, hairband, improvised gag, kneehighs, kneeling, long hair, multiple girls, pantyhose, rope, school uniform, serafuku, short hair, sitting, skirt, socks, sweater vest, tape, tape gag, wink