Used to milk test at a farm that used a surge milker like in the pictures, for their fresh and treated cows. It was a stanchion barn and it was easier to use the pail. They always put the strap over the back and a bit forward of center on the cows, never saw it moved behind the hips. They milked over 100, bringing the cows in 20 at a time on each side and always had one or two in the bucket. cows never raised a fuss and it couldn't fall off when it was across their back well in front of the hips.