flake out 
phrasal verb with flake verb [ I ] uk/fleɪk/ us/fleɪk/
  informal            
 UK突然睡着;(因疲倦而)倒下 
to suddenly go to sleep or feel weak because you are extremely tired
  I got home and flaked out on the sofa. 我一进家门便瘫倒在沙发上。 
  US行为古怪 
to do something strange or not do what you are expected to do 
  I'm tired of relying on other people - they keep flaking out on me. 我再也受不了需要依赖他人了——他们个个都怪怪的。