Remember that the edge of cut batting will shrink back into itself!
SO when you cut batting, cut it an inch or more larger than the edge line you want, to allow for that shrinkage.

I put it in the dryer with a load of clothes. After 10 mins. pull out and stretch it out over backing and smooth as I pin/

if I'm using pre-packaged batting I open it up and put it over the bathtub curtain rail for a day

This reminds me of a question I have meant to ask -- I read that Warm 'n Natural should be washed before using. . .but this doesn't sound right to me. Anyone have experience with this?

The package I just opened reads, "Quilt Warm and Natural right out of the package. Pre-washing is not necessary. Once quilted, machine wash and dry. Stitch up to 10" apart. There will be a 3% shrinkage with the first wash."

Then it listed directions for optional pre-use washing instructions.

Thanks. It was in a quilt book that listed all kinds of batting that I saw the notation. Do other quilters order their batting from specialty sites rather than using the generic stuff a fabric store would carry? I am batting-knowledge-ignorant.

I made the mistake once of leaving batting out overnight to relax the creases. It was so full of cat fur (hmm...wonder how that happened? No one knew a thing!) by morning that I had to throw it away and use another. Now I just toss in the dryer w/ a damp washcloth for a few minutes. Between that and being careful when smoothing out when I spray baste, I haven't had any more problems.

My batting is on a big roll, so I just unroll what I need and cut, then proceed on.

I put my batting in the dryer with a moist towel for 5 minutes or so and it comes out fluffy and ready to use.

Suggestion when you start to bind your quilt go open your package of batting. If it's a day or two that's great it's easier to work with.