Feeling like you already had sex with someone. Also, having sex with someone again.
"Hey, do you know that girl? I feel like I've seen her before. Wait, didn't I sleep with her? Oh man, I just got a wicked case of deja screw."
When you know what is about to happen is not good, because it happended before and you feel it's about to happen again.
"I think he will be faithful this time."
"Wake up. You're about to get deja screwed."