In both our silicone and hard plastic flanges, the base of your nipples (where they connect to the areola) should go at least far enough in the tunnel that they're past the sharp turn under the flange where the funnel meets the tunnel (deeper is even better). Your phone camera or a mirror can help you see under the flange.
If you're having a hard time getting deep enough in the silicone flanges, see How to Get Deeper in Silicone Flanges.
Reviewed by Diana West, IBCLC
July 15, 2021