When I "machine tack" my quilts, it's more like stitching in the ditch, but just for a half an inch or so. I learned this from my niece about 15 years ago. It's almost invisible. I just stitch in the ditch for 3 or 4 stitches, back stitch 4 or 5 stitches and then go ahead another 3 or 4 stitches. None of that has ever come out. It's fun and fast and durable.