Genius slipper design where you knit a short "scarf", fold and sew onto your bottom. Garter stitch extra chunky yarn about wide, and however many rows you need, then sew into the 2 layers of the felt bottom.
МК Спицы "Пришивная" планка [ "This is in Russian but the photos are good. Attaching a knit placket", "Find and save knitting and crochet schemas, simple recipes, and other ideas collected with love.", " (Ideas from the Internet) / Crochet / Women