Originally Posted by quantum-x

Poppers are anything in the alkyl nitrate family - used to be amyl nitrate, now usually butyl nitrite or isobutyl nitrite.

Amongst other things, they temporarily relax smooth muscles in the body, so make insertion easier. Not to mention they also give a very strong rush at the same time; you enjoy the rush and forget the insertion, I guess.

They're also used for just before an orgasm to intensify it.

So now you know.