Cardi B Shows Off New Mother's Day Watch, Gives Mom Advice to Rihanna

Cardi B was the perfect person to ask about mommy duty on Mother's Day -- especially since Rihanna is about to become one herself -- and her sage advice is ... (cue video).

The rapper was leaving Carbone Sunday night in NYC next to her hubby, Offset, and at least one of their kids (looks like Kulture) ... and Cardi chopped it up with our photog before getting into her waiting SUV about a lot of stuff, including words of wisdom for mom-to-be RiRi.

Check it out ... she says motherhood is something that comes pretty naturally, and she thinks the same will happen for Rihanna when the baby comes -- which should be any day now.

We also asked about Roe v. Wade, but she wasn't as chatty about that. What she did clarify, however, was her stance on fame ... and seemingly being done with it, which she alluded to about a week or so ago in sorta dramatic fashion.

Luckily, CB sets the record straight with us about what she meant ... and it sounds like she was mostly referring to her online presence more than anything. So, no -- Cardi's not scrapping music altogether. Good to hear!