Something more subdued and mundane but along the same lines is surprisingly pleasant. This is for the ladies on the board only .

Walking braless under a t-shirt. I simply ran out of bras and while they were in the wash, wanted to take a walk. So I decided - what the heck, no one knows me anyway.

It is so pleasant! Both the sense of motion and the friction of fabric against the nipples; highly recommended. And it is such an easily available pleasure. No cost!