Her 1-year-old son, Kingston, has been traveling with the 37-year-old singer on her "The Sweet Escape" tour.
"I go from the tour bus to the hotel room to the concert venue -- all while carrying my baby," Stefani tells InStyle in its September issue, on newsstands Friday.
"He's just getting into music. He does the whole head-bouncing thing," she says. "I love him so much. He's the best thing that has ever happened to me."
Kingston is the first child for Stefani and her rocker husband, Gavin Rossdale, 39, who were married in 2002.
"Obviously I'm in a race to have another, but I don't want to do it while on tour," Stefani says. "And I want to do another No Doubt record."
"But I can't wait to get pregnant again," she tells the magazine. "It's so fun and consuming and romantic."
Stefani became a staple in the music world with the 1995 release of No Doubt's "Tragic Kingdom" record. British-born Rossdale, who fronted Bush, made his American debut with the more sober album "Sixteen Stone."