"I spoil my nephew," Kardashian told PEOPLE at the 7th Annual Leather and Laces Super Bowl Party that she co-hosted with Holly Madison and Roselyn Sanchez. "He really loves me; I already know it. He never cries every time I hold him."
"I take pictures of him all day and we have a really special bond," she continues. "I know I'm his favorite aunt."
Not Khloe? "No, I'm his favorite aunt," she laughs.
And Kardashian, 29, says that she's not above bribing him with gifts. "I gave him these little onesies that say Mason Dash Disick," she says. "They were adorable."
Big sister Kourtney, 30, gave birth to Mason with beau Scott Disick in December. It has been a growing experience for them both. "He has changed Kourtney's life," says Kardashian, "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."
Mom Kris Jenner agrees that Mason had brought new joy into everyone's life: "I will babysit him anytime, anywhere," she says. "He has just brought the whole family so much happiness. We're all really blessed."