An erection acquired during an Oxycodone high. You can keep it hard for hours. The downside is that you can't actually cum. Just like you can't piss, which is another side effect of it.
And yet another reason to stay away from it. It's expensive, has terrible withdrawal symptoms and your dick don't work anymore. Not for you, anyway, your girlfriend on the other hand will be happy with the results.
I got an oxyboner last night and and fucked my girlfriend like 5 times until she couldn't take anymore and fell asleep. For the next 3 hours I beat that shit off, I choked it like it owed me money, I slapped it around like uh...something that slaps shit. And I got no creamy goodness. Nada. Nothing. Zilche.