While on a trip to Tokyo with model daughters Delilah, 19, and Amelia, 16, and "teenage model wrangler" Erika Jayne, Delilah revealed to her mom that she learned "how to give head" from Lisa's "sex book."
While at dinner, Delilah and Amelia told Lisa and Janye that there was a video that had gone viral of a girl who films herself eating food.
"Don't you watch porn instead of people eating?" Jayne asked the girls.
"Maybe I don't want to know about that yet," Lisa said, laughing.
Then Delilah revealed, "I'm not gonna lie, but your sex book taught me how to -- I was like 12 when I saw this -- it literally teaches you how to give head."
A stunned Lisa was stunned, replying, "Well, if you're gonna learn it, you better learn it right."
"I never thought in a million years that my own children would read the book," she confessed to the camera, holding up a copy of Rinnavation: Getting Your Best Life Ever, before reading a couple of particularly dirty lines from the book.
"How could I have put this in a book?" she said, laughing.
The Real Housewives of Beverly Hills airs Tuesdays at 9 p.m. ET on Bravo.
Photo credit: Instagram/@lisarinna