Tyga is SO sweet! He took a Goyard dop bag full of cash to Polachek's Jewelers in Calabasas to pick up a quick gift for girlfriend Kylie Jenner. We'll give you ONE GUESS as to whose $$$ that was in the bag ... so thoughtful of T-Raww to spend Kylie's money on Kylie!

That wasn't his only Christmas contribution to the family, the rapper got down on the dance floor with mom Kris as the momager shows off her moves. He kissed Kylie under the mistletoe with Santa and Kylie posed with sis Kendall and dad Caitlyn at the holiday bash. All in the family!