When inhaled, poppers cause blood vessels to dilate, allowing more blood to reach the heart. They also cause blood to rush to the brain, speed up heartbeat and relax muscles, providing an intense high lasting a few minutes at most. The drug is widely used to intensify pleasure whilst dancing and having sex. Sniffing poppers relaxes the anal sphincter muscles allowing anal sex to take place more easily. As poppers dilate blood vessels, many men find that they lose their erection when sniffing them.