cut off sleeves of t-shirt. make armholes as big or small as desired...
cut different sizes and lengths in scrap fabric (use whatever you have around, old t-shirts, skirts, sheets, tights). go wild, make scraps as torn and messy as possible.
gather each scrap at their respective top
staying parallel to the shirt's hem, sew scraps onto t-shirt. overlap and align however looks best. enjoy!