Lets say we raise to 4bb w/ 100bb stacks, BB calls. So 9bb pot. Cbet 7bb, get raised to 21bb.
Pot is 9+7+21 = 37bb. We have to call 14bb and have 89bb behind.
That's 2.5:1 on the call, and 9:1 if you win his stack.
You need to win another 30bb to BE, if you're only playing to hit your draw. So you could probably lay down here a lot and not have a huge leak. Obviously this doesn't take into account 3betting big draws.