Nick Lachey and Vanessa Lachey on March 30, 2012 in Sydney, Australia. Credit: Don Arnold/WireImage

Motherhood isn't for the faint of heart. Just ask Vanessa Lachey.

"I haven't slept since September 12," the Wipeout host, 32, tells Us Weekly of her round-the-look care for 8-week-old son Camden. "It takes so long to feed and change and swaddle him. But it's worth!"

Lachey -- wed to singer Nick, 39 -- is sharing her new tricks as spokeswoman of P&G's Have You Tried This Yet? campaign. The Charleston, South Carolina, native opens up to Us.

What's been your toughest challenge?

I think the diaper thing. His first blowout, I made two rookie mistakes: No. 1, I didn't put a diaper underneath the old one, and No. 2, I didn't let him finish. Nick and I laughed ourselves to tears.

How is Nick handling diaper duty?

He's the best! I'm really lucky. He changes them a lot. Since I nurse, Nick sees that as his bonding time. He'll talk and sing to him while doing it.

So sweet! What are Camden's milestones?

He's smiling at the sound of our voices now. He's so peaceful -- he just sits there and takes it all in with his bright blue eyes. He has his daddy's eyes!

Advice for new moms?

Don't be scares to accept help. If someone wants to come over and cook or clean, take it!