Slip slip knit or SSK is a basic way to decrease stitches. It makes a decrease that slants to the left and is often paired with knit two together, which is a right-slanting decrease.
To execute this decrease, slip the first stitch as if to knit, slip the second stitch as if to knit, then slide the left-hand needle into the front part of both stitches and knit them together.
Some people also perform this decrease by slipping the first stitch as if to knit and the second stitch as if to purl, working them together through the front as with the standard decrease.
This makes it look a little more like a knit 2 together decrease, so if you're mirroring decreases on a garment you might want to try it.
Also Known As: SSK