Also, when working the PFB stitch, you are essentially cramming two stitches into a space fit for a single stitch. Things get very tight in the stitch you are working the PFB into, especially if you are a knitter who naturally knits with a tight tension. If you see abbreviations like PFB or P1FB in your knitting pattern, you are creating two stitches from a single stitch (known as an increase). It is most often used on the wrong (or purl) side of one-sided patterns like stockinette but can be utilized as a decorative element on the right (or knit) side as well.
How to Purl Front and Back (PFB)
Purling in the front and back of a single stitch can be a little complicated at first, but it makes perfect sense once you do it. Work through the following steps while knitting, it is much easier to understand with needles in your hand. After a few times, it will seem natural. During the PFB stitch, you will be purling twice into the same stitch—once in the front loop closest to you and once in the back loop farthest from you. This creates a twist that tightens up the increase. If you do not move to the back loop on the second purl, you will get a hole in your knitting that is very similar to a yarn over (YO). This feels pretty awkward the first couple of times you do it. Once you get the hang of it, you will be increasing on the purl side in no time.
