I pump my breasts on a regular basis, and I use "nipplefunwear" teats to extend my nipples.

I have punched two holes in the cups of an old bra so that indoors I can wear and fill the teats (4XL!) with full support and suction. But I would be arrested if I ventured out with a tight top! Plus I regularly need to clear the creamy discharges I now get. 

When I wear my regular bra, it pushes my nipples back, negating my hard won, and sometimes painful nipple extension.

I have seen Medela breast shields, which seem to have a soft disk which grips the extended nipple, plus a hard shell which protects its extension inside the bra. It seems I could wear these whilst preserving my nipples, whilst not looking too titty. I looks like that they would hold any leaks as well.  

Has anybody used these aids?

I thought breast shields would be to train your nipples to point out rather than be inverted.