Okay, so technically this bind-off is usually referred to as the sewn bind-off, but I think that name fails to communicate just how awesomely stretchy this method is. (Do you remember Stretch Armstrong? I remember seeing the commercials as a kid and wondering exactly how long it would take to get tired of a toy whose only feature was stretchable arms and legs. Not long, I thought.)
But enough about 80s memorabilia. On to the tutorial!
The sewn bind-off is perfect for toe-up socks. You'll need to leave a tail of yarn at least 2 feet long when you're ready to bind off, which you then thread onto a tapestry needle.