The Lecture You Would Never Want Your Parents To Give You - Ch. 21 - The Bentou shop owner trying his best to suppress his inner evil thoughts

[beep_repair]

All signs point to her wanting to have a threesome with her daughter, yes.

The mom was doing it on purpose.

Eh, based on the chapter title, this is a joke about the shop owner's attempt to suppress his "evil thoughts", not about mom teasing/flirting. Suggesting 3-way incest to a stranger would also be way out of character for both Mrs. Hornypants and the series she stars in. Mom's all about dad-D.

The girls are just ordering a common lunch item. The shop owner is letting his imagination run away with him.