Bokutachi wa Benkyou ga Dekinai - According to some fans and in wiki. December 28 is the Birthday of Mafuyu-sensei. So, anyone here in Manga readers can confirm it, and please screenshot

Study Group = Harem. BokuBen Review

Mafuyu Kirisu, We Never Learn Wiki

Bokutachi wa Benkyou ga Dekinai, We Never Learn

Joeschmo's Gears and Grounds: Bokutachi wa Benkyou ga Dekinai S2

Bokutachi wa Benkyou ga Dekinai! Episode 2 Discussion (20

Bokutachi wa Benkyou ga Dekinai: Kirisu Mafuyu Sensei. #bokuben

Bokutachi wa Benkyou ga Dekinai celebra el cumpleaños de Mafuyu

Bokutachi wa Benkyou ga Dekinai - Here's another Mafuyu-sensei

Now We Can Study about Mafuyu's age and Bokuben history. : r

Bokutachi wa Benkyou ga Dekinai Plush

Study Group = Harem. BokuBen Review

June 2019 – RABUJOI – An Anime Blog

Bokutachi wa Benkyou ga Dekinai! Episode 2 Discussion (20

Mafuyu Kirisu, We Never Learn Wiki