Heidi Klum Martin Kristen sunglasses kids tank dress

Heidi Klum and Martin Kristen took her four children back to school shopping in Brentwood on Monday, and Leni, Lou, Johan and Henry all took turns holding hands with their mom and her bodyguard beau.

When she's not in parenting mode, Heidi is known to post risque photos on her Twitter account, and last week she fired back at critics who think she should cover up. "I always think everyone who can't handle a photo should unfollow me right now," she told Access Hollywood.

But what about when her kids reach the age where their classmates are Googling the former Victoria's Secret model and stumbling across her sexy pics? That's going to have to be a discussion at some point...