f you

It means hello pull the middle finger for better use

f you howve you been

When you F up

When one does something really bad they will regret later (unless they have no conscience at all).

I knew a guy who planned a school shooting cuz he got upset over a rumor of him and a girl. Turns out he was joking though he got a felon and it was all over the news. That guy is an example of When you F up.