Yes, pin the points. Please don't cry. You could also use a dot of glue on the edge or seam tape. It's worth the extra time to make sure they don't slip out of place. Did you see this one?
https://www.youtube.com/watch?v=xJenRhhbi4A
This one is cute too. Love the touch of whimsy they add to a project!
https://www.youtube.com/watch?v=LULOyPepTm0