They use a range of recreational drugs.

It's pretty dangerous what they use. Look up a pornstar by the name of Michael Stefano (AKA Mike Long). He shot himself up with some sort of drug concoction to help him maintain an erection. However, after shooting three scenes Michael Stefano found himself experiencing an extremely painful priapus condition, basically, his erection wouldn't go away. After 23 hours of this torture, Michael Stefano went in for emergency surgery, and his doctors ended up cutting a pair of holes in the head of his member in order to drain it. He then had months of problems getting an erection at all.