Having successfully inserted your side seams, you should now have two ginormous fabric oblongs that you need to turn into tubes. No problem!
Bring your two long, raw seams together with right sides of fabric on the inside. Pin those long seams together, beginning from the crotch, as above.
Take your work to the sewing machine or overlocker. Sew and finish these seams. Take your work back to the ironing board and press that seam. I’m going to tattoo Press Seams on my forehead. Or maybe not… I found a sleeve presser really useful for this stage. I found mine in a charity shop.
Two tubes that look like mirror images of each other:
At this stage, you’ll likely panic that you’ve cut out the wrong size. These are way too big! Put that panic to one side. It’s all gonna be fine.
Next, I show you how to sew the crotch seam, including a top tip to ensure perfect meeting of intersecting seam lines!