When you have passed the normal amount of frustration to be frustrated. It can also be applied to express feelings of sexual frustration.
Carl: hey have you beat zelda yet? you've been playing it for like four hours straight...
Jimmy: dude don't even go there. i am so fuckstrated with this game right now, you have no idea.
or
Carl: hey you and Kathleen have been going out for like a year now..have you banged her yet?
Jimmy: naw man she won't even let me get past first base, I'M SO FUCKSTRATED!!!