This bind off methods join 2 pieces with only one bind off, without further seam.
You will need : your 2 pieces, placed on two different needles, and a third needle.
Place the two pieces right sides facing one another, on two different needles, points going the same way.
With 3rd needle, knit together the first stitch of front needle with the first stitch of back needle. You get one stitch on 3rd needle.
Knit together the next stitch from front needle with the next stitch from back needle.
You have 2 stitches on 3rd needle.
Pass first stitch on 3rd needle over the last stitch.
You have one stitch on 3rd needle.
Repeat steps 3 and 4 until you have only one stitch left on the 3rd needle.
Cut and pull yarn.
From the right side
From the wrong side.
You can work the 3 needle bind off on the right side, with wrong sides facing one another. Here how it will look on the right side.
On the wrong side