How to prevent shirts from rubbing my nipples while running?

Damn!
I just felt a little chafing on my 5 miler on saturday and I used a cool max shirt as my bottom layer.

I usually use cool max also as a bottom layer and that is what this was but for some reason the cool weather gave me a case of hard nipples and my sweaty shirt just rubbed my chest raw. OUCH. That will be a good reminder to at least pull my shirt up and behind my head if I start sweating to much.