Three short lines hold a whole small drama. We begin in a high meadow, an open, quiet place, and then the poem moves to a kiss that is described as "grazing." That word does double work. It suggests a light, barely-there touch, the way lips might brush a cheek. It also fits the meadow, where animals graze, and the title, "Ruminant," points the same way: a ruminant is a grass-eating animal that chews its food over again.
That second meaning seems to matter. The speaker appears to be turning over a memory, chewing on it slowly, much as a cow might. But the last line, "lost to sleep," says the kiss slips away, perhaps because the speaker drifts off, or perhaps because the memory fades in dreaming.
The mood is gentle and wistful. Nothing is dramatic, yet there's a quiet ache in how fragile the moment is, something tender that can't quite be held onto.