Sekai Bunka-sha published the second book in the series titled Ofuro de Nandeyanen (What the Heck Are You Doing in the Bath?) in 2017, followed by Yūenchi de Nandeyanen (What the Heck Are You Doing at the Amusement Park?) in 2018, Mahō de Nandeyanen (What the Heck Are You Doing With Magic?) in 2019, and Umi de Nandeyanen (What the Heck Are You Doing at the Beach?) in 2022.
::
Japanese publisher Sekai Bunka-sha announced on Tuesday that Hirotaka Nakagawa, Tsubasa Suzuki, and Hiroe Aoki’s Nandeyanen The project’s teaser video reveals that the light anime will exclusively stream on Netflix in Japan starting on December 1.
::
Sekai Bunka-sha published the first Nandeyanen picture book in 2013.
::
Suzuki and Aoki, without Nakagawa, were credited for the text and illustrations of the four most recent books in the series.