Negative Dope is a cool way to describe something that is the complete opposite of dope (meaning good). The term can be used when referring to something that is bad or negative but also to show your support when a homie is feeling down.
"Man, yesterday I ate these dope ass chocolate chip cookies before I went to the library to pick up chicks like I always do on tuesdays. But for some reason my swag was completely turned off and I couldn't connect with a single girl. I'm starting to think that those cookies were negative dope!"
"You know how much I love penguins, right? Well last week I went to the North Pole to see them live, you know. Turns out they don't even live there. They apparently live at the South Pole..."
"For real, dude?! Damn, that's negative dope son! Was it worth the trip though?"
"Well, a polar bear ate my right thumb but other than that I had a good time. I really wanted to see some penguins though."
When something is not awesome or when something is going really bad. That's negative dope.
"I always make bad results when I'm eating Toffefee before the thing. "
"Man, that's some negative dope"