This video knitting tutorial will help you learn how to knit the purl two together through the back loop decrease (p2tog tbl). This method of removing stitches from your work is used when decreasing purl stitches. It complements the p2tog decrease and creates a left slanting stitch on the purl side.
Step 1: Take working needle insert it into the second stitch on the main needle from behind going through the first stitch
Step 2: Pull working needle around front
Step 3: Yarn over working needle
Step 4: Push yarn through both stitches
Step 5: Slip both stitches off main needle