What’s the cause of a hard-on that doesn’t work?

Firm but not erect should be the penis neck hardness is good but erection angle is very small (<90 degrees), may be related to individual physiological factors, penis root ligament damage. The angle of erection varies between individual men, with most men having an angle of erection greater than 90 degrees (horizontally upwards), ranging from about 120 degrees to 130 degrees. About 10% of men have an erection that is tight against the belly, and another 5% or so have an erection angle of less than 90 degrees (downward). Damage to the ligaments around the root of the penis that hold it in place, especially the suspensory ligaments of the penis, may also result in a smaller angle upward and a larger angle of movement from side to side when the penis is erect. Generally speaking, it is normal to be able to complete sexual intercourse and be sexually satisfied.