Every cigarette you smoke will affect your erectile capacity, and in the long run it can lead to impotence
. The nicotine in tobacco smoke is a vasco-constrictor which means that it narrows the blood vessels and reduces the blood supply. The penis gets erect from the pressure of the blood that rushes to it when you get sexually aroused. But because of the poor blood flow, it can decrease in its capacity to remain rigid for sexual penetration. Smoking
can also affect men's sperm, which can reduce fertility
and also increase risks for birth defects
. You are well advised to quit immediately.