How do you carry from the jungle when you can't safely farm?

Hello again, GD. I was watching a few of my friends play recently (I haven't been able to play for a few days due to serious connection problems) and they all main jungle. The most recurring problem they had in games they lost was that they couldn't farm their jungles because their lanes all lost too hard, and the enemy just made it theirs. In this situation is it okay to steal lane farm and group/make a play if you can, or are you supposed to risk farming your jungle and hope your lanes help you out if you get caught? How do you turn that situation into a potential win?