Cottongin rhymes with:
baillargeon, bogin, colgin, cragin, curmudgeon, dolgin, durgin, edgin, elgin, feagin, glycogen, gougeon, hagin, hanjin, hodgin, iljin, jarnagin, magin, maginn, misogyne, mongeon, pidgeon, plasminogen, pridgeon, ragin, repligen, rodgin, spurgeon, spurgin, tianjin, turgeon, virgin, yeargin, ynjiun