After Odysseus kills all of the suitors what must he so for Poseidon?

After Odysseus kills the suitors, he must make a sacrifice to Poseidon to appease the god and seek his favor. Specifically, he is required to travel to a distant land, where he must plant a oar and offer a sacrifice of a ram, bull, or boar to Poseidon. This act demonstrates his respect for the god and ensures safe passage home, as Poseidon had been angered by Odysseus's actions throughout his journey.