Oga is a character from Elf-san wa Yaserarenai. She is an ogre in which, like other characters in the series, her tastes in humane consumption, more specifically alcohol, has caused her stomach to soften. As a result, she goes to a sauna often to wash away the beer belly.
Appointment 5: Ogre Heat Wave Edit
When Erufuda and Kuroeda go to a bathhouse with a sauna, they're surprised to see that its setting is cranked up to 120º Celsius. As it turns out, Oga was using the sauna, and being an ogre, she's used to the high temperatures. The two elves try to use the sauna regardless of the insane heat, and here, they learn that Oga has somewhat of a beer belly similar to Erufuda's french fry tummy. The two of them decide to do an endurance contest and the one who loses has to buy the winner the restaurant item of choice. Erufuda loses almost instantly and Oga gets to drink some beer.