Nipple Meter Edit Meaning

1.

using the nipple as a means to tell the outside temperature

I stepped out in the snowstorm in only a t-shirt, and because my nipples were sticking a foot off my chest, my nipple meter read "cold as fuck"

2.

a gauge of temperature when you step outside on a cold day

Damn boys, my nipple meter says it's pretty fuckin cold out here.