I have near zero sensitivity in my nipples. Light stroking and rubbing does absolutely nothing for me. I've found that something REALLY hard pinching will do something but not much.
Almost same here, so I had one nip pierced one year ago.
Sensation has been heightened slightly. What I enjoy
often 'mindlessly' I play with the piercing over my regular
shirt or stick my hand under my tank top - I enjoy doing
this for myself in public or private. Do not know if anyone
in public has noticed or not.
When I masturbate I have play 'lightly' with the piercing as fuel.
I like my pierced nip being played with 'lightly' by the other persone
if I am really turned on to that man.