The speaker begins with a strange, generous wish: if they could, they would pay the sea. The reason is that the sea carries messages from "my other life," a life that feels close but out of reach. The sea becomes a kind of messenger, bringing news across a distance the speaker can't cross alone.
The last lines turn more personal. "My other mouth" suggests a second voice, perhaps a freer version of the speaker, and it gives a simple instruction: take joy, and don't be quiet. The title, "Carnival," fits that message, since carnival suggests noise, celebration, and letting go of restraint.
The mood is wistful but also quietly defiant. There's longing in the first lines, then encouragement in the last. The poem seems to say that joy is something to claim out loud, even when part of your life feels far away, and that the pull toward it may come from some deeper part of yourself.