"I take pictures of him all day and we have a really special bond," she added. "I know I'm his favorite aunt."
Kim's older sister Kourtney and beau Scott Disick welcomed son Mason Dash Disick in December. "He has changed Kourtney's life," Kim dished. "She's so happy; she's such a good mom. And Scott is such a great dad. It's been really exciting to see the two of them grow up so much."
See photos of the Kardashian sisters' skimpiest outfits!