Poppers are common with gay men as when they are inhaled they make you want to fuck or be fucked.

They also relax your throat, vaginal and anus muscles making penetration easier especially good for anal.

For men they make you get the urge to fuck, gay bottoms want to be fucked and so do women.

Good uses include anal, fisting, extreme penetration, gangbangs or swinging or just general/casual sex.

I have personally never used them but keep meaning to give them a try.

Best way to find out why is to buy yourself a good anal dildo and a bottle of poppers and see the results for yourself.