We can all be a bit nervous about sex. Alcohol and drugs usually make everybody more relaxed and less inhibited. Some drugs are also regarded as aphrodisiacs, things that promote sexual desire and performance.
People often say sex is more fun or spontaneous if they have had a few drinks or are high.
This means making sure you only do what you want to do and not doing things you will later regret. If you don't want sex don't be pressurised into doing it. If you do have sex use condoms - look out for the kite mark on the packet. Even if you or your partner are taking other precautions against pregnancy, still use a condom. If you are having anal sex, you must use an extra strong condom and a water-based lubricant like KY jelly.