Sheshach is an atbash cipher for Babylon. This once proud country has been seized. Thus Babylon has become an object of horror to all the countries. The strong waves of the sea have covered her land. Her cities are horrible. They are like a dried up desert, where no one lives and no one even passes by.
Then Yahweh via Jeremiah taunted Babylon, by indicating how they thought that they were superior with their plundering and rejoicing. They were like young heifers and stallions doing whatever they wanted to do. Now their mothers will be shamed and disgraced. They will become the last of the countries, as their land will become a wilderness, a dry land, like a desert. The wrath of Yahweh will not be held back. Babylon will be deserted and become an utter desolation. Everyone who passes by her will be appalled. They will hiss at all the wounds that they would see.