Such a responsive nipples! even before children. Did nursing. change her responsiveness? My own wife’s nipples usually get hard only one at a time. The only time they both go erect together is when she is about to cum. It’s like those little pop-up thermometers when you’re cooking a turkey. As long as her nipples stay erect, I know to keep going, she needs more. Once they relax, I need to stop; she is satisfied.