most likely your snake is fine. they sometimes go a while without pooping. and if you're feeding him a smaller rodent than what he should be taking, even longer. when you feed, you should be able to see a slight lump in his belly when he gets the rodent all the way down. if not, next time feed a little larger and check again. if you decide to soak him. get a tub from walmart, doesn't have to be real big. but your snake should be able to move some in it. and the water should be luke warm to you. what's warm to you is hot to your snake. you don't want the water too deep that your snake has to swim. half way up the snakes body is fine. put a few air holes in the lid and place it on the tub. also check and make sure his hot spot is around 88 to 92 degrees F so he can properly digest his food. keep us posted. good luck don