Fee, Try hand expressing alittle before attaching Cooper. When your breast is full your nipple would be flat so by expressing alittle first it helps o draw the nipple out & soften the breast to give him something to hold on to.
Some people find that by cutting the tip of the nipple shield off it helps with weaning them off it. Just start of witha tiny snip & slowly cut it bigger till its gone. Do it over a few days though, not just a few feeds.
And yes I think it should be placed so Coopers Chin is touching your skin.