How to get an elastic edge when binding off / casting off

In this DROPS video we show one way to bind off / cast off to get an elastic edge, like you can find in DROPS 186-13.

Work like this:
Cast off with knit from the right side as follows: Knit 2 stitches, * insert the left needle into the 2 stitches on the right needle from left to right and knit them together, knit 1 *, work from *-* until there is 1 stitch left on the row. Cut the strand and pull it through the last stitch.