The 32-year-old model and television personality shared details about Miles, her 5-month-old son with Legend, and her 2-year-old daughter, Luna, in an interview with E! News published Tuesday.
"He loves being told he's handsome," Teigen said of her son. "He really lights up."
"Miles is so reserved -- he's just John. He's just a cuddly, lovable little ball," she added.
The Lip Sync Battle host said Miles' quiet personality is a stark contrast to Luna, whom she described as a "nutcase."
"He loves the quiet moments. He loves story time, but Luna was just such a bull," the mom-of-two said.
"From the moment she came out, you just knew she was going to be such a Luna -- just a nutcase. he's not really into anything. He loves sleeping and milk," she added.
Teigen shared a video this month of herself with Miles, Luna and her mom, Vilailuck Teigen. The clip shows Luna protesting at being filmed.
"This is going well," Teigen joked in the caption.
Legend said on the Big Boy's Neighborhood podcast in August that he and Teigen would "like" to have three kids. The couple married in September 2013 after meeting on the set of Legend's "Stereo" music video.