TheJapan-Dominated Universe is a universe Brian and Stewie Griffin visit in "Road to the Multiverse". In this universe, the United States never dropped the atomic bomb on Hiroshima or Nagasaki, so Japan never gave up, and everyone is Japanese. Specifically, they see the effects on Quahog, Rhode Island. It is unknown if in this universe, Quahog, or any other cities for that matter changes its name after World War II, and any residents have their names affected.
Japanese Peter tells Japanese Meg she is dishonorable, and she commits seppuku, a ritual suicide. Then Peter farts in her face. Chris laughs he did so. Then, Glenn Quagmire barges in, saying he likes a lot of sex. Stewie and Brian them come saying they like but don't like each other. This is a common theme in Japanese story traditions where former bad characters join with good characters to fight a greater foe but there is still mutual distrust.
Then, Lois walks in, bringing to Peter food for his penis. He said it was hungry two hours ago, and then punches her, and she crawls away giggling.