>>11304042
https://www.amazon.com/Pcs-Nipple-Corector-Inverted-Massager/dp/B0DHDDVJSS/ref=sr_1_2?sr=8-2
my favorite has been these kind of pumps, together with those small clear suckers (i got some of those from temu recently and they work great)
tried multiple different nipple vibrators but they all suck
using your hands and fingers on your nipples is the best way. You need to build up sensitivity in your nipples, probably wont feel too much at the start. For me it took around 1-2 weeks before it started feeling good