Shun is sharing his tangerine and ends up going to Kaname's house, but Chizuru, Yuki and Yuta end up going too and all 5 stay for dinner. While it was expected they would leave after dinner, instead at Chizuru's suggestion, it becomes their first 5 person sleepover.
It's your fault for eating 
tangerines out there.
Es tu culpa por comer
mandarinas allá afuera.
Culpa tuya por comer
mandarinas afuera.
É sua culpa por comer 
tangerinas lá fora.