Three short lines, and the poem is already over. A man is alone in the midday heat, and he takes a look at his own testicle. That's all the poem tells us, and it's what makes it work: it treats something intimate and slightly awkward as a plain, ordinary act.
The title, "Inspection," gives it a clinical air, as if the speaker were checking a piece of equipment or doing a medical self-exam. The poem doesn't say why he looks, so we're left to guess. He might be worried about a lump, or he might just be curious. The speaker doesn't tell us how he feels, but the flat, matter-of-fact tone suggests a mix of vulnerability and self-conscious calm.
The mood is quiet, exposed and a little comic. "Alone" and "noon heat" make the scene bright and still, with nowhere to hide. The poem finds a small, honest humor in the body's strangeness and in the way we sometimes study ourselves when no one is watching.