Working into edge half-stitch of the knitted piece, *bring tip of threaded needle in and out of a knitted stitch, place working yarn under needle tip, then bring threaded needle through the stitch and tighten. Repeat from *, always bringing threaded needle on top of working yarn.
Insert threaded needle under two rows, right next to the selvedge, and up through both layers of fabric. Count back one row and insert the needle under the next two rows. Continue this circular motion-ahead two rows from where the working yarn emerged from the previous row, and then back one row.