wool - n - gather

Slip, slip, purl, pass 2. This is a centred double decrease on the purl side. It's a tidy stitch but can be a little tricky.

With yarn held in front slip the next two stitches knitwise individually from the left hand needle to the right hand needle, return both stitches to the left hand needle, insert the right hand needle into both stitches as if to purl both through back loops and slip them from the left hand needle to the right hand needle, purl the next stitch, insert the left hand needle into both slipped stitches and bring it over the purl stitch and off the needle.