well in my experience women dont like huge veins on guys LoL but if you still insist it is easy to bulge them just put a lot of pressure were the bicept and shoulder mustcels meet{dont know the real name for the muscle I think it is deltoid but not possitive} I think if you bulged them a lot they would increase in size but bulging them may hurt the veins I would think. but I have a friends with realy big veins who does that all the time I would bet it is pretty safe to do. Of course thats all theoredical I have a little evidence to back it up though I did that before I even tought about making veins bigger now they bulge out pretty big.