Heidi Klum's latest project 'Seriously Funny Kids' is a little like Bill Cosby's 'Kids Say the Darndest Things.' The supermodel turned super-mom's half-hour unscripted series premieres next month and will feature Klum interacting with children and bringing out the hilarious and insightful things they say.

But Klum tells PEOPLE when it comes to her own four kids, she and husband Seal don't think swearing is any laughing matter.

"When we're around the children, we really make a point in our family not to curse or say potty words," she says. "My husband and I try our best to make sure our kids are proper and have good manners."

Klum, who also co-hosts 'Project Runway' with her "other husband" Tim Gunn, admits she still swears from time to time in front of her friends. "I'm not saying I'm a saint by any means," she says. "When I'm with grown-ups and we're out, I curse sometimes and we say some inappropriate things. But when we're at home, [Seal] and I try our best to make sure our children are proper and have good manners."