I've only done it a couple of times. My hope is that the quilt will not be as "crinkly". I've used warm and natural both times I've preshrunk batting. I just wet it with warm/hot water in the sink, squeeze it out and dry it in the drier. It worked fine.
(I do not wash before gifting.) Sometimes, I prewash the fabric, sometimes, I don't.
It was easy. I encountered no problems with doing it. However, I'm not sure how it turned out after washing.
bkay