I don't know about SO2, but methane's got to be pretty low, judging by the atmosphere and oceans on Titan. The condensation point is WELL below zero, even at one atmosphere.
At any rate, you're not going to see methane condensation in normal terrestrial conditions...otherwise, you'd see methane condensation in swamps in cold weather. I'm willing to bet the same applies to SO2.
Which means that the real question is: what is the water vapor content of a fart? And even though I said "vapor"...let the obvious jokes commence.