I've been seeing a guy for a several months now. The sex is really good but one thing I've noticed is that he never seems to get fully hard. It doesn't affect his ability to be able to get it in me but it's not something I've encountered before so have no idea if it's normal or not! He also had to drink a can of Red Bull before we had sex last time (though he was getting over a cold then) and can only do it once a night. Seems that once spent he can't get it up again - something else I've not encountered in a man before.
He's only early 30s and doesn't take drugs or any medication so I have no idea whether not getting totally hard is common in men or not!