Sweat and Tears (Expert) is the first stage in Sports Day Awakens!.
Seconds after the stage begins, a boss wave is spawned. Rampage Cats and a Doge appears. Snache and Croco will be spawned as a distraction and will keep coming. If you don't advance quickly, Metal Doges will appear as well. Ginger Snache then shows up after a while, followed by Dark Otter. They'll keep spawning until you destroy the base.
Meatshielding is essential against the peons and the boss itself. Bring along Catornado if you have, or any quick critical hitters to get rid of the Metal Doges. Having tanky units that can withstand the damage of several Rampage Cats such as Crazed Mythical Titan Cat is helpful, as well as Awakened Bahamut as soon as possible to keep pushing it back until you reach the base (if you have it).