How to Knit Mattress Stitch
Mattress stitch is used quite often. It does not form a thick edge and allows you to pull several colored parts or the stripes of patterns together, as it is performed on the front side. For example, this seam is used to make side seams and shoulder seams.
Mattress Stitch Technique
Using the long thread tails, pick up a stitch close to the edge of one side, pulling the two edges close. Push the needle through the opposite side and repeat until the area required is neatly closed.