Hi welcome to the health care magic It s not necessary to make penis iron like solid while erection. It should be hard enough to penetrate vagina and to do full penetrative intercourse Avoid stress if you are having in routine life Make foreplay practice before sex Rule out following causes if you are feeling problem in erection.. _high blood pressure _diabetes _obesity _prostate problem _smoking _alcohol _beta blocker, diuretic drug history etc If specific cause found than treated accordingly Take healthy diet with fruits and vegetables Take care Hope your concern solved If needed consult psychiatrist for help and further discussion