i found a tutorial on this by deramores. they have a pdf copy of it. and new stitch a day has both tutorials and a video.
this is worked on a even number of stitches.
Step 1: Cast on 2 stitches
Step 2: Knit 2
Step 3: Pass first stitch over second stitch
Step 4: Knit, pass first stitch over second stitch
Step 5: Knit, pass first stitch over second stitch
Step 6: Knit, pass first stitch over second stitch
Step 7: Slip stitch back to main needle
another method
Picot Cast-Off Edging
Cast off Row: Cast off 3 sts, * sl last st back on to left-hand needle, cast on 2 sts, cast off 4 sts, rep from * ending last rep, cast off 5 sts.
Working picot row, (A): Cast off the first 3 stitches, * sl the last stitch used in casting off from the right-hand needle to the left-hand needle. Working into the stitch returned to the
left-hand needle, cast on 2 stitches. Working picot row, (B): Cast off 4 stitches on left-hand needle. Rep from * across the row, but for the last rep, cast off the remaining 5 stitches.
personally i found watching the video more helpful.