Trying to recall anti-pointiness tip

I saw, somewhere, (it may have been on a KnittingHelp video) a tip for eliminating the pointiness that occurs when you come to the very end of a cast-off row and simply form a loop and pull the yarn end through it.

Can anyone tell me what I am forgetting?

Apparently when you come to the last stitch, you pick uo the stitch below it, put it on the needle next to the last stitch, and knit them together… or something like that… to get a nice castoff edge.