Unersättlich

Use the Vomit Inducing Agent consumable. You can get this recipe from talking to Maxime in Boulder Town, near Natasha's clinic.

This achievement has no cultural references in the English and Chinese versions. It is likely specific to the game. If someone is "Insatiable," it means that they are impossible to satisfy, whether it be their appetite or desire. I don't think something called the "Vomit-Inducing Agent" can fulfill your stomach.