At times when pinning two pieces of fabric together, you may find a bubble.
Sometimes this happens because cutting wasn’t precise or one piece of fabric may have been to stretchy. In any event, if you sew it while pinned in this way, you will get a bubble or a crease after you’ve pressed it. Not only is it a bit of an eye sore, but it can throw off the rest of your piecing the quilt top.
So, in the middle of the bubble put a pin. If there are two more bubbles on each side, pin in the middle of those bubbles. Continue to do that until it is fairly smoothed out.
Here is a video demonstration.
If you have any questions, please write in the comment box and I will answer it, or e-mail me at firstname.lastname@example.org.