I once used a back patch, I think on my neck or shoulder. The adhesive bothered my skin. I wonder if they would stick to a base layer. I don't typically do long rides when it's cold but I can think of days when it would have helped to have something like this to warm up after a ride.
I put it over my baselayer and it worked fine. If you have a second, somewhat tight layer you can sandwich it in.
Sarah
When it's easy, ride hard; when it's hard, ride easy.
2011 Volagi Liscio
2010 Pegoretti Love #3 "Manovelo"
2011 Mercian Vincitore Special
2003 Eddy Merckx Team SC - stolen
2001 Colnago Ovalmaster Stars and Stripes