Nowhere in any of the baby-advice books is there a chapter telling parents how to deal with wobblers and toddlers who become groupies before they are 3 years old.

Nor should there be, at least if the band of affection is The Wiggles.

Sometime between pregnancy and teething, when I truly believed the “Barney” craze would be over before my toddlers could even utter the purple dinosaur’s name, four gentlemen from Australia sneakingly became the latest rage among the wiggly, giggly diaper set.

Now these four zany men in brightly colored shirts who call themselves The Wiggles have captured the hearts of my toddler-age daughters, MaggieBeth and Lauren, and in this case – and this case only – I don’t mind it at all that they have become groupies.

Or should I call them Wigglers? I like that better. It fits their nature.

The Wiggles are bringing their energized stage show to Boston on Monday and Tuesday, with three sold-out shows each day. They’re performing at the Berklee Performance Center at the Berklee College of Music. My two Wigglers will be attending one of the Boston concerts, and like true groupies they expect to meet the men who keep them dancing.

The shows are part of the Wiggly Safari tour, the same title of the 11th video by the group in less than three years in the United States alone. The distribution of so many tapes in such a short period of time could be viewed as oversaturation of the American children’s market, but in practical terms the number is less than a new season of children’s programs. According to trade reports, the award-winning children’s group is nearly a billion-dollar business, and the gentlemen are keeping tight reins on the purity and copyrights of their worldwide enterprise.

The Wiggles are more comfy-cozy to the toddler set than the diapers the wee ones are wearing, even though the group’s formula for success isn’t anything new. For decades, other hit children’s programs such as “Captain Kangaroo” used the same ingredients – a likable core character or team, notable sidekicks that bolster the niceties of the leads, a running gag and slapstick skits that deliver roars.

But The Wiggles seem to possess a secret, indescribable element, a touch of magic that makes wobblers and toddlers get off the floor and onto their feet so they can “point their fingers and do the twist.” Children are prone to imitate what they see – a child development theory – and The Wiggles mimic movements they know children already make at their age or that they soon will be.

Everything about The Wiggles – from the music and dances to the costumes and the sets – is based on principles of child psychology, and most of those philosophies say to keep it simple. Use bold colors, but sparingly, repeat words or phrases often, and show children bouncing around to the beat.

The men are identified by their signature color – Greg Page is the yellow Wiggle; Murray Cook is the red Wiggle, Anthony Field is the blue Wiggle and Jeff Fatt is the purple Wiggle. And although each of them is unique, it’s their combined talents that have created a sensation that’s educational while being charming. It doesn’t hurt, either, that three of the four Wiggles have college degrees in early childhood development.

Murray Cook, the red Wiggle, said the madness called The Wiggles is easy to create because it’s “coming from a child’s world.”

“We know how children think,” said Cook, in a recent telephone interview. “We really know how to speak to children.”

And there’s nothing pompous about what Cook says. The Wiggles have an approach to educating and entertaining children that is patient yet practical. Their gentle voices aren’t intimidating, and their catchy jingles are so basic that over time they are easy for toddlers to remember and recite, over and over again.

“I think the bottom line is it’s just good fun,” Cook said. “I think children recognize that we’re having fun.”

The true entertainment value derived from each tape, however, comes from watching your own children dance or sing along with The Wiggles, hunching over to stomp like a bear or dramatically falling backwards when Captain Feathersword, the friendly pirate, says, “blow me down!” And it’s still cute, most of the time, when they are crying over and over again, “mooorrrah, pleeeese, wigglahs, pleeese, wigglahs.”

Every day it’s the same, a refrain bellows from the television that gives my children a jolt of kindness. “Hi! I’m Greg! I’m Murray! I’m Anthony! I’m Jeff! And we’re the Wiggles!”