i just finshed the last of 3 flannel quilts for my 3 grandsons.....all of the above suggestions are great, pre washing or not is a personal preference (i do not), and it does stretch more, so my suggestion to you is PIN PIN PIN....i found when i did not pin, coz i was just doing a short sashing on a block, the fabric moves and i always ended up with it being uneven....so even with those short runs, pin it up........gina