To puss out. To back out of a commitment out of malice, spite, or plain cowardice. To be "that
guy." That means to be
the one guy who goes against what everyone wants. You want Mcdonalds, he wants Burger King etc.
You: "Hey Corey, let's go to this party. There are
girls there that totally want to do us."
Corey: *Pretending not to hear you* "Hey, let's go to my
house."
You: "Dude, stop being that
guy. You're Coreying out."