The mother-of-two shared a behind-the-scenes clip from an at-home photo shoot ... and, in it, she reveals she and her husband Carter Reum could barely get Phoenix to keep still -- a recurring problem, she says, since he's able to walk on his own.

Watch the vid ... Paris is trying to hold back her squirmy eldest child -- but, he's not having it, and Reum holds his hand and walks with him on his escape from mom's arms.

Good thing Poppa Reum strolled with his baby boy too ... 'cause the kid nearly pulled down a light for the shoot on top of himself which would've complicated his otherwise simple life.

As you know ... Paris is a mom to two tiny tots these days -- one-year-old Phoenix and daughter London, who's around 8 months.

Unlike other celebs, Paris has no issue showing her kids' faces ... and, admitting to each parenting faux pas. She's made mistakes on social media and been called out -- kindly -- by other parents, like when she put Phoenix's life vest on backward.

Each time, Paris has thanked moms online for all the great advice she's getting ... and, it seems she enjoys sharing all of the big moments of her parenting journey.