A gnat falls into a glass of wine, and the speaker, instead of fishing it out or tossing the drink, simply sips around it. It's a small, almost lazy act of tolerance. Then the tiny insect drifts to the side of the glass, sticks, and comes back to life. It crawls all the way up to the rim, and the speaker is moved enough by this to drink the rest in two big gulps.
The tone is dry and good-humored. The speaker isn't solemn about the rescue, and the last line has a wry twist: the gnat's survival "inspires" a drink rather than a grand realization. Maybe the gnat's struggle is a model of persistence, or maybe it's just a good excuse. The short, broken lines, with "pin- / prick" split across a line break, mimic the slow, hesitant progress of the insect. The mood is quiet, warm, and a little mischievous, finding a tiny drama in an ordinary evening.