stimulate

Baby powder.

I use Alboline, a make up remover made out of Petroleum Jelly, wax and mineral oil that has been recommended as a sex lubricant by a number of sex advisors. It's sold at Walgreens and CVS in the U.S., in the same area as facial cleansers and moisturizers. I put the Alboline this on my nipples and then use my thumbs to gently rub them a circular motion. The Alboline keeps them from getting chaffed or raw due to the rubbing. It's also good to rub for a bit then take as rest as your nipples tend to get over-sensitized. But, I can tell you that the nipple stim is what really got things going for me and still does to this day. I can feel my prostate beging to engorge the minute I start to rub them. I also love it when my wife sucks them during sex. Give it a try.

i use baby powder, any oil/liquid seem to kill the sensations. Light touches are best.

Definitely a dry powder like talc (talcum powder) or starch works better than liquid. And, yes, very light touches are best.