I'm just rough guessing, but I think it may have something to do with a Tanuki legend. Not sure if it represents the one where the Tanuki was trapped in a pot or something though.
Its a pot full of sake and the ladle is for scooping said sake.
Kasen is an oni, which means she can outdrink them until they vomit and then some. Oh and since onis are super OP, they can't turn down her drinking request without her smashing their faces in for refusing to drink with her.
It's from a specific issue of Wild and Horned Hermit.
Mamizou annoyed with how close Kasen is getting to Reimu plans to drive her off. Mamizou spreads various anti Oni charms about which makes it hard for Kasen to keep her identity hidden. Of course she rubs this in Kasen's face. This is loosely represented in the top panel.
Kasen plans to get back at Mamizou. She sets up a drinking party at Reimu's shrine and provides the sake (the pot and ladle). Mamizou eager for free booze and wanting to beat Kasen at drinking crashes the party with her 4 minions. Kasen slipped oil into the sake which is apparently a Tanuki weakness and it makes them all very ill. This is loosely represented in the bottom panel.
It wasn't as much oil slipped into the sake, as much as just BEING oil entirely. "Douju's Jar, filled with a never ending amount of Oil"
The Tanuki were just so drunk at this point, that they couldn't taste the difference and kept on drinking to stay in the contest. Tanuki however somehow become EXTREMELY drunk on oil very quickly, to the point where they are unable to move and essentially become a free, easy kill.
