"Just how hard is a penis supposed to get?"
How hard is a penis supposed to get? My erection is never rock hard though I have normal orgasms.
There’s a plethora of reasons why your erection’s not Hollywood-hero-hard (would James Bond ever only be semi-erect?). Physical factors include your age, how tired you are, what medication you’re on, whether you’ve had too much to drink or indulged in drugs and how often you recently had sex. Then there are emotional influences like stress and performance anxiety (I bet you haven’t lost a wink of sleep worrying about this, have you? Course not).
Fact is, erections are as fickle and individual as their owners. Some men’s penises are so hard, you could hammer nails with them. Others could finally bed the woman of their dreams and still only fly half-mast. The rest hover somewhere in between - sort of where you are really.