So I looked up bind off methods online for double #knitting. Hated all of the ones I could find (One wasn't invisible, the other involved an embroidery needle... neither stretched well) so went by instinct, tried a few things and found my own. My method does not separate: Both yarns through--mind the correct color is in the front. Slip colors to match. Color A with color A, knit2t B with B knit2t. Repeat instruction 1. Works well for rib.