Dax Shepard scratches his daughter's head "extremely hard" to get her to fall asleep.

Dax Shepard and Kristen Bell on their parenting ups and downs

Dax Shepard and Kristen Bell on their parenting ups and downs

The 46-year-old actor - who has daughters Lincoln, eight, and Delta, six, with wife Kristen Bell - revealed the trick he has learned to use on his younger daughter at bedtime.

He said: "I figured out that if I scratch my younger daughter's head extremely hard­ — her request — she is out cold within 90 seconds."

The 'Armchair Expert' podcast host appeared alongside his 'Frozen' star wife on PEOPLE magazine's 'Parents' video series, where he also shared that a recent television ban proved to be "barbaric" for the pair.

He added: "I gave a 'no TV for the weekend' consequence, which was later revealed to be a barbaric punishment for us", with Kristen confirming "Yeah, that will never happen again."

The showbiz couple then went on to share some grievances of parenthood that they wish they had known beforehand, with Kristen struggling to cope with the unexpected noise her children make.

Kristen said: " I guess I thought they're littler people, right? They might be less loud. And they're not! The volume is three times what a normal person should be, and the problem is it's not just volume, it's the consistency of noise. It's like having NPR on all the time — so two stations of NPR on all the time — but if it were all questions. No answers, no fun stories, just all questions. And that's a lot."

Meanwhile, Dax revealed that he wished he was prepared for the destructive mess created by small children, as it took him and Kristen six months to accept the inevitable.

He said: "I wish someone had let me know that I will never have anything nice again.

"That would've been a good heads-up," he shares. "If you like that there are no crumbs and toys on your floor, say goodbye to it. The quicker you come to accept that you're gonna live in a pigsty and that everything will be vaguely broken — the quicker you can accept that, the happier the experience is. We fought it for like six months."