"We're total rivals," she told "The Tonight Show" host Jimmy Fallon on Tuesday. "Dada is banned in our house!"
Further arguing as to why "mama" should be her baby girl's first word, Lively joked about her handsome hubby, "He's pathetic! I do everything, he does nothing."
The former "Gossip Girl" star also revealed that the first-time parents might be working on a redesign of their daughter's room for when she's older that will suit their overprotective behavior.
"Her room has no windows. We cannot have a child, our daughter, go in with a boyfriend and do anything terrible," she explained to Fallon." We need a chastity window! That's a new form of contraception."