This method is really helpful if you've just missed a yarnover within the previous few rows.
Be careful not to use it too frequently within one row or section! Because of the yarn stealing that happens if you use it too frequently it will cause a tight spot in the knitting that will be more likely to break during blocking. If you are missing more than 2 yarnovers in one section, I would recommend unknitting those rows to the missing yarnover and then add the missing yarnover in and rework the rows you just unknit.
Steps for Stockinette:
Find where you're missing your yarnover 0:30
Slip to the right spot without changing orientation
Grab the right loop, rework any rows above and put the stitch on your needle 1:30
Steps for Lace Swatch:
Find your missing yarnover 3:35
Slip to the right spot without changing orientation
Grab the right loop, rework any rows above and put the stitch on your needle 4:28
The most common way to loose a yarnover 2:43