This photo, from the story of Gulliver's Travels, illustrates spiritual warfare which is all around. And how little things can defeat us. Why not share it with your group and learn from it?
In the world of alternative churches, btw, I have read precious little about sin. But it is quite real nevertheless. The old writers would say that if we do not kill it - it will kill us. Or to quote an Apostle: For if you live according to the sinful nature, you will die; but if by the Spirit you put to death the misdeeds of the body, you will live. Romans 8:13.