The feeling after sex, usually right after you cum. The feelings of jizz-kill include: regret, self-esteem issues, awkwardness. Also jizz-kill explains why you aren't attracted to the person anymore after sex.
Bill- Hey how was Sheena the other night?
Matt- Not to good. The jizz-kill was pretty bad. As soon as we got done having sex, I almost cried.
Fictional car part used in context to fool people who think they know a shit-load about cars. The object is to get the shit-talker to admit if he/she has ever heard of the "Bob-Rod". Usually takes 2 participants for the joke.
tyler-"God, I hate changing Bob-rods, such a bitch."
Rmack-"yeah, I know."
Miles(joke intended for)-"what's a Bob-rod, I've never heard of that and I've worked on cars all my life."
Tyler-"You never heard of a Bob-rod before?"
Tyler-"Are you serious?! YOu've never heard of a Bob-rod?!"
Miles-"Well...I think I've heard of something like that before....."