Cardi was hot as fish grease when she hopped on IG live -- taking issue with our story about whether she's going to diss Nicki Minaj on some new music she's recording.

She's also pissed about the photos of her and baby Kulture on a Miami hotel balcony. And, she's pissed because she claims that photogs were stalking her. For the record, we weren't involved in taking those pictures -- but they did come to us, and we did post them.

While unloading -- for nearly an hour from the backseat of her ride -- she said celebrities didn't sign up for this, but insisted she could handle it ... 'cause she's a "tough bitch."

She also ripped into fan blogs, some she's had to block, and compared the music industry to the strip club biz. She said stripping is exactly like being a rapper in many ways, but also made it clear ... "I don't want to go back to the strip club!"

And, then there was the sex talk ... LOTS and LOTS of sex talk. Cardi shared in graphic detail why she knows Offset's never leaving her. In a nutshell, "Cardi B got that fat bitch p***y." And, that's the tamest thing she said about her sexual skills.