When I really need to relieve some pressure and nothing else is workin (yeah right) I will have a quick 5finger shuffle...this is not a good habit to get into, mind you.
Other than that, having quick solo sessions SUCKS for working on your stamina, so it's all about drawing it out as long as possible without losing your hardon - edging yourself to the point of orgasm, where you feel 1/2 contractions, then stop, grasp firmly a few times and breathe til it subsides - great habit to get into, as the final orgasm is really explosively intense, and you're buillding up how long you can last...
OCCASIONALLY I will get real stoned or tripping a lil on some 2c-x, and have an epic wank session from anywhere between 1 - 5 hours. But not often, like once every few months...You really need nothing to do, and I'm constantly busy, so it's not cool.