Lie to the kids.

"It's because, um... it's really fashionable."

One of the boy's cocked their head to the side. "What's fashionable?"

"Not wearing pants..." clarified Katie.

"Or underpants!" giggled the first girl again.

"No, what does it mean?" repeated the boy.

"Fashionable is what famous people wear," offered someone else.

"Oh."

"Famous people go naked?!"

"That seems wrong."

"Can I be fashionable?"

"Oh! I want to be famous!"

"No, no, it doesn't work like that," Katie frantically tried to explain. "None of you are allowed to be fashionable like me."

"Sure I can!" a pigtailed girl replied confidently. "Just watch!"

The girl stood up from her chair and quickly stuck her hands under her sundress stripping her leggings and panties down to her ankles in one fell swoop. She lifted the front of her dress proudly displaying her bare crotch to the table.

"See?!" pigtails exclaimed. "I can be fashionable!"

Suddenly a second girl's privates were on display when one of the boys pantsed her without warning. A retaliatory pantsing brought the boy to run away, but as his own bottoms dropped to his ankles he tripped and fell to the floor cackling. Within moments the entire table was either stripping themselves of their pants or tugging on their neighbor's, much to Katie's horror.