The rapper went on IG Live Saturday and was dressed in a lovely little onesie that showed off all her best angles and curves -- and while she split her time between talking to her audience and doing some beauty work ... she also found time to do some twerking.

We've seen it all before, of course -- and it's great every time -- but here ... her little dance number is very Christmas-y, and we gotta say ... it's kinda making us feel naughty watching!

Anyhoo, there was more that was addressed during the live stream ... including what sure sounds like a shot at Spotify users. MTS says the streaming service is ... well, for kids. Ya gotta wonder if there's a subliminal barb in that somewhere ... something tells us there is.

At any rate, good to see Meg bringing us holiday cheer and an eyeful of body-ody-ody. 👀