I have never been on a ride with a baselayer, except for one time, when I pretty much wore two short sleeved jerseys on top of each other, hah (just to experiment). I've never really had a problem other than the occasional descent.

I cannot find any base layers that seem to fit me in that kind of snug/skin-tight fit. Have tried Craft, PI, and Specialized. I guess maybe I should look at UnderArmour Heatgear Compression shirts? or kids sizes? hah.