While appearing on Tuesday's episode of "The Tonight Show Starring Jimmy Fallon," the model spoke about being a "cool aunt" to her 18 nieces and nephews, noting that two more are on their way, including sister Kylie Jenner's second child with Travis Scott. Kendall, 25, also shared how Devin, 24, is with the children, revealing that one of her nieces has the "biggest crush" on him.
When Fallon, 46, asked about Kendall's babysitting skills, she said, "I'm alright. I always want to be the cool aunt and liked, I guess, by all of them."
"It's really fun," she added of being an aunt. "I try to be chill."
As for her NBA player beau, the reality star said Devin "loves" the kids and has a special bond with Kylie and Travis' 3-year-old daughter Stormi in particular. "He loves them," Kendall told Fallon. "Him and Stormi have an amazing relationship. She has the biggest crush on him and I'm jealous sometimes. I'm like, 'Stop ... can you guys not?'"
Meanwhile, the 818 founder went on to share that she and her boyfriend can be rather competitive with one another -- at least when it comes to basketball. After noting that she played a little of the sport in middle school -- but "was not that good" -- Kendall said she and the Phoenix Suns player "sometimes" play one-on-one and recalled recently facing off in a game of basketball in the pool against him.
"We were playing in the pool and he just took it way too seriously -- as did I, by the way," Kendall shared. "I had the ball and he was guarding me and it was a whole thing. He actually ended up cutting my hand open a little bit with his nail because he took it a little too seriously."
"It's pretty much healed now, so you can't really see it, but it was a big gash and it bothered me for, like, two weeks," she added.
Kendall and Devin reportedly began dating in June 2020. However, the couple has been rather private about their relationship and didn't make their romance Instagram official until February 2021.
"I feel like it's always worked better to me that way," she told reunion host Andy Cohen. "No offense to my older sisters at all, but I think that Kylie and I specifically have had the opportunity to watch my older sisters go through marriages, relationships and breakups and all of these things and do them pretty publicly."
Kendall continued, "It was a personal preference from a really young age that I didn't really want to ... I think it makes my life a lot easier and our relationship a lot better to be completely honest."
"I just feel like it's a private matter. It's not really for anybody else to judge or know."