is a Japanese web manga series written and illustrated by Katsu Aki.

It was serialized on Shogakukan's eBigComic4 website from December 2018 to April 2021.

Written and illustrated by Katsu Aki, We Started a Threesome!

[3] Shogakukan collected its chapters in three tankōbon volumes, released from September 30, 2019,[4] to June 30, 2021.

[5] In North America, Seven Seas Entertainment announced in March 2023 that they had licensed the series, and the first volume is set to be released in December of the same year.