im going out on a limb here, but maybe your just not hearing the right things, there are subtle invitations that you have to be on the look out for. you'll know them when you hear them if your paying attention.
ask a lot of questions too, keep them talking, ask them how there day went, how such and such made them feel etc etc etc.
most of all, dont whack off.
i believe testosterone plays a large part in things and if your balls are hurting that is a big incentive to try and get laid.