Check the roll is on the outside: otherwise it'll be inside out. If you're unsure, blow lightly into the condom and it will unroll slightly, making it easier to spot which way is the right way round.

 

Squeeze the condom teat so there's no air trapped inside, and, still squeezing the teat, put the condom on the top of the penis and roll it down with your other hand.

 

If you feel it start to roll back up during sex, roll it down again immediately. If it comes off, stop what you're doing, pull it out by the open end and put a new condom on.

 

Once the man comes, and while the penis is still erect, hold the condom by the base and withdraw. Then take it off, knot it, wrap it in a tissue and throw it in the bin (not down the toilet - think of the planet). Never re-use a condom: if you think you're in for a long night, go adequately equipped.