Includes feeling regretful,and outlandishly weird after a sexual encounter. Usually on one night stands. Most notably, you are not attracted to the person afterwards.
Bob -"Hey Dude...did you fuck her?"
Joe -"Awe shit man, it was a Jizz-Kill Theory."
Joe - "After I got done, I felt like I wanted to hang myself."
Bob - "YES! I warned you about the Jizz-Kill Theory"