To begin, cast on 3 extra stitches at the beginning of the row you’re going to bind off. (You can do this using the Cabled Cast On, Knitted Cast On or Loop Cast On – whichever is most comfortable for you.)
*Next, knit two stitches and slip the third stitch knitwise.
Knit one more stitch. You will now have 4 stitches on your right needle.
Use your left needle tip to pass the slipped stitch over the last knitted stitch. This will leave you with three stitches on your right needle.
Slip these three stitches back onto the left needle tip, purlwise. Tug on the working yarn to tighten up the stitches.