Amphetamines
Just like alcohol, amphetamines, methamphetamine and MDMA (ecstasy), will make your horney, but tend to take away your ability to do the deed. Many men in fact find that amphetamines make achieving and maintaining an erection very difficult.
Cocaine
Cocaine is both a stimulant and irritant, this can cause erectile dysfunction, painful erections and other issues such as difficulty maintaining an erection or ejaculating and many find this frustrating.
In small doses, cocaine will cause excitement and euphoria, which the user may interpret as sexual excitement. However, continued use will lower your libido, and because cocaine is addictive your desire for cocaine will eventually overtake your desire for sex.
Heroin
Heroin tends to reduce sexual responses in both men and women. Men will have more difficulty maintaining an erections and achieving orgasm, while women on heroin will produce less vaginal juices making them feel "dry" making it hard for them to orgasm as well.
GHB
GHB is a very dangerous drug that you can overdose on very easily and is often used for date rape. The assaulter can secretly put the drug into the victim’s drink, and rape the victim when s/he is unconscious. Victims of this sort of date rape often do not later remember that they have been assaulted.
Nicotine
Nicotine can affect erectile tissue and the muscles involved in producing an erection, thus causing impotence. Men who smoke tobacco are twice as likely to be impotent as non-smoking men of the same age. Using nicotine in combination with cardiac drugs, antihypertensive medications or vasodilators drastically increases a man’s probability of complete impotence.
Marijuana
For the first half hour after consuming marijuana you will experiene body high or a mental high determined by the type of marijuana used. A mental high will make you feel euphoric and hyper while a body high will make you feel tired, calm, and relaxed. Even though it can give these two different feelings and even lower libido and sperm count, many people find sex under the influence of marijuana to be especially enjoyable.