The rap trio came on "TMZ Live" Monday to tell us about the coolest part of their collab with Rita -- all the money from it is going to the MusiCares COVID-19 Relief Fund. Treach, Vin and Kay Gee told us exactly who will benefit from the fund ... and turns out, his timing couldn't be any better.

Fact is ... several people working behind the scenes on some of the biggest records and musical performances we all enjoy are struggling immensely right now, and NBN wanted to make sure the proceeds from their remix with Rita went directly into those folks' pockets.

Of course, this all comes after Rita posted a video of herself rapping to the classic '90s tune -- which then turned into a full-fledged collaboration between her and the boys here. The remix features Rita rapping in place of Vinnie ... and she plugs in seamlessly.

As for how Rita got this good at rapping the song, well ... the fellas get into that story too. Turns out, she had to learn it for a movie role -- and the rest is hip-hop history, as they say.

There's another silver lining too in this joining of forces -- Naughty By Nature tells us the renewed interest in their music couldn't have happened at a better time, when people are at home and have nothing but time on their hands to discover old gems.