But oh, good Lord, the verse you makeIt gives a chap the belly-ache. (5-6)
Terence's buddy is so annoyed with all his sad mopey poems that he complains they cause him physical pain. It's just a joke, but it ties into all kinds of imagery that links life and poetry and drinking to physical suffering. This poem is really keyed into the human body—what we put into it, how it feels, when it hurts, when it doesn't, etc. It helps to ground the whole poem, to keep it from floating away into some fancy world of abstract ideas.
The world, it was the old world yet, I was I, my things were wet, (39-40)
It's a bummer when your stuff gets wet. That's an experience we've all had. The fact that Terence brings it up here is a sign of his genius for putting things in simple, comprehensible terms. He doesn't give us a long philosophical discussion of the loss of happiness. He just points out that, because he got drunk, his things got wet. We fill in the rest with our imaginations—how uncomfortable he must have been, how he got dry, etc.
Out of a stem that scored the hand I wrung it in a weary land (51-52)
In this line Terence compares writing his poems to hard, physically painful work. It's like squeezing juice out of a plant that cuts his hands. Even the land is "weary" and suffers along with him. It's all part of the deal. Life stinks, then you die. Okay, maybe it's not quite that bad, but Terence wants to remind us, over and over again, that there's plenty of sadness and suffering in life, and that's what we need to prepare ourselves for.