if you know for a fact that she will break up with you if you tell her than dont tell her...you can hide the nut shrinkage by getting some HCG and doing it through the whole cycle. thats what a couple of my friends do....works like a charm they said and yes I know that shit sucks when they shrink up and my girlfriend makes fun of me but she is only fucking around because she supports me doing gear...hope this helps bro and good luck
