Smoking - drinking alcoholic beverages - doing drugs - all interrupt blood flow to your penis resulting in diminished libido cause erectile dysfunction or impotence.
Read information below.
Definite Don'Ts
Alcohol kills reproductive cells and decreases sperm viability. It also disrupts the link between the brain and the penis. Immoderate use of alcohol inhibits the creation of the male sex hormone, androgen.
Substance abuse. Chronic use of drink, marijuana or other drugs often causes erectile dysfunction and decreased sexual drive. Stress, anxiety or depression. Other psychological conditions also contribute to some cases of erectile dysfunction. Smoking. Smoking can cause erectile dysfunction because it restricts blood flow to veins and arteries. Men who smoke cigarettes are much more likely to develop erectile dysfunction.
Getting drunk does not cause erectile dysfunction. But the excess of alcohol does prevent the blood from flowing properly, which does cause that you don't get an erection like you would have wanted. This being said, you'll be fine the next morning and be as per normal.
Years of drink abuse may become a cause of erectile dysfunction. But in young male 3/4 pegs can in fact prolong the ejaculation as the drink dries up the passages and one has to exert for long time to get ejaculation.But on the other hand too much and abnormal quantity in one go of alcohol if taken by old or young can leave the person incapable of normal sex.
Of course it does (or can) while the male is drunk. Even ancient philosophers used to say that drink gave the desire but removed ability.