It should raise your test levels, actually. Test levels rise in men who use Cialis, not because Cialis raises your test per se, but because having sex more does.
I've had sex while on cycles (even with a girl who was also on a cycle!) and can say it's not going to hurt you. Unless you're the on the receiving end. Not that there's anything wrong with that...Which is fine, and a choice you need to be comfortable with. There's nothing to be ashmed of.