Originally Posted by
dunster
You can lay the two pieces of batting next to each other and hand stitch back and forth (whip stitch). The stitches don't need to be tight or close together for it to hold long enough to do the quilting. Or you can tape the pieces together using a fusible. I wouldn't overlap them if the batting is fluffy because it will probably show up in the finished piece.
This would be my suggestion as well. In fact, have done it one more than once. Works like a charm. No bulges/puffiness and doesn't take long at all.