I did a quilt for my daughter. One of the pieces in the block is flannel. Somewhere in the picture section is a picture of it.....
Anyway....the pieces are square/rectangle and I think the name of the pattern I used was Just Can't Cut It.
I just had to be careful not to stretch the flannel. It had some "give" to it, but it worked out fine. The quilt has been washed a few times and it's fine. No shrinkage to it...but like I said, I washed it before I made it.