There are two types of condoms: external, which go on the penis, and internal, which can be used vaginally or anally. Make sure they are in date and have a quality mark on them – and carry more than one, in case you put it on wrong and have to throw it away. (It may get some pre-ejaculate – the fluid that is released from the penis prior to ejaculation – on it, which may contain sperm. There is an STI transmission risk, too.)

Put the condom on the penis before it goes near where you want to put it. The penis must be fully erect. If you have a foreskin, you may find it more comfortable if you pull it back first. Make sure the condom is the right way round. Squeeze the air out of the tip, then gently roll the condom down the penis, far enough to get a good grip. Anything oil- or fat-based will “eat” a latex condom, so use a water-based lubricant. Wash your hands if you have been eating anything greasy.

There is a myth that you needed to use extra-strong condoms for anal sex. As long as you are using a good lubricant, and plenty of it, it doesn’t matter. Manufacturers recommend condoms are used for no longer than about 30 minutes at a time, but that is quite generous, considering that the average time penetrative sex lasts between four and six minutes.

After a man has ejaculated, his penis will go flaccid quickly, so he will need to withdraw from his partner fairly soon, while holding the base of the condom.

Mel Gadd is the manager of a sex education project for the Family Planning Association. She was talking to Emine Saner