'Scary Mommy' Jill Smokler: Moms don't magically have all the answers

"There should be a code of ethics among mothers," says Jill Smokler, author of the Scary Mommy blog and a new book, released today, called "Motherhood Comes Naturally (and Other Vicious Lies)."

Among her suggested ethics rules? Don't contribute to tooth fairy inflation: "We have kids whose parents play the tooth fairy and give them a $10 bill, a $20 bill. Sets the bar way too high for the rest of us."

And for pity's sake, don't give another mom's child a pet, even a goldfish at a carnival. "You just don't do that," Smokler told TODAY's Hoda Kotb.

Smokler, whose three kids are aged 5, 7 and 9, has created an open, honest and often hilarious community at Scary Mommy. She shared some of her own mommy-fail moments on TODAY with Kathie Lee Gifford and Hoda Kotb, confessing that she frequently makes the wrong medical call: Taking a baby to the E.R. for gas, for instance, while thinking that a broken arm was just a minor bruise.

"I always make the wrong call," Smokler said. "It's not always as easy and natural as you want it to be. I think the love part is easy, but you know, having all the right answers and the solutions is not."