Mou Kodomo ja nain da yo? | I'm Not a Kid Anymore, You Know?

Jeanne Dack Pounding Kid 01

Same-themed manga about kid fighting female ninjas from japanese imageboard.

Kodomo Janaishi! | I'm Not a Little Kid!

[Hochidonmai (Donburako)] Kids Know-It-All-Know-It-All-Know-Who-Go-Na-Na-Kid-Stream ★ ★

(C99) [sagejoh (sage joh)] Mou Kodomo ja nain da yo? | I'm Not a Kid Anymore, You Know? [English] [Nisor]

[Yakisoba Pants (Hiiragi Popura, Grand Deer)] Yanmama o Gaki no Sugata ni Natte Fukushuu NTR | Revenge NTR of a Yanmama in the Form of a Kid [English] {Doujins.com}

Older woman & kid body swap

(C84) [Karasuma Pink Higashiiru (Karasuma Pink)] Niwa ni wa 2-wa Niwatori ga Iru (Kid Icarus) [English] [Yuuta's Blog]

[Hidemaru] Kodomo ni Natte Okashi Makuru yo! Ch. 5 | Become a Kid and Have Sex All the Time! Part 5 (COMIC MILF 2013-06 Vol.13) [English] [Sergio]

(C90) [Karasuma Pink Higashiiru (Karasuma Pink)] Delivery Angel Land (Kid Icarus) [English] {TheRobotsGhost}

(ShotaFes 3) [Pometeor (Enotou)] Shinyakuseisho (Kid Icarus: Uprising)

[Homunculus] Boy meets Girl (COMIC Kairakuten 2018-09) [Chinese] [無邪気漢化組] [Digital]

(C47) [Cafeteria Watermelon (Kosuge Yuutarou)] GIRL IN THE BOX (Marmalade Boy)

[Natsume Tsuna] Hijitsuzai Shounen Shoujo | False Reality, Boy & Girl (COMIC Koh 2017-10) [English] [Constipat8 & CrowKarasu] [Digital]

(SC46) [ONIGIRIZ (CUTEG, Hypar)] IM@SWEETS 3 GIRL MEET BOY! (THE iDOLM@STER Dearly Stars)

(C72) [will's (Takasakin)] Otokonoko Version Onnanoko Version | Boy Version Girl Version (Kyo Kara Maoh!) [English] [SugarParade]

[Otono Natsu] Boy Friend (Oh! My Girl) [English] [desudesu] [Decensored]

[Motsu Aki] Sekai Saikyou no Onna VS Chounai Saikyou no Shounen | The Strongest Girl in the World vs. The Strongest Boy in Town (Girls for M Vol. 15) [English] [Digital]

(C73) [Dasshifunnyuu (Nishi Iori)] RANDOM.BOY MEETS GIRL

(Futaket 12) [Rei no Tokoro (Kuroarama Soukai)] BOY MEETS GIRL [English] [Risette]

(Futaket 12) [Rei no Tokoro (Kuroarama Soukai)] BOY MEETS GIRL

[Shirota Kurota] Otoko x Kouishitsu x Onna | Boy x A Locker Room x Girl (Scape Goat) [English]

[Arai Kei] Doutei Otoko to Toramimi Onna | Virgin Boy and the Tiger Eared Girl (COMIC Megastore Alpha 2015-01) [English] [Hot Cocoa]

[Ozaki Mirai] Boy Meets Girl 2 [Chinese]

[DISTANCE] Shichau? - A cherry boy meets a busty girl.

[Fuuga] Otokonoko Onnanoko | Boy Girl [English] [Decensored]

[Otono Natsu] Boy Friend (Oh! My Girl) [English] [desudesu]

(C81) [Noritama-Gozen (Noritama)] BOY x Niku GIRL (Boku wa Tomodachi ga Sukunai)

[Yanagawa Rio] Tsundere Musume VS Doutei M Shounen | Awkward Girl VS Virginal Masochist Boy (Doutei Ouji) [English] [SubDESU-H]

(C80) [DIEPPE FACTORY (Alpine)] Boy x Meats x Girl (Boku wa Tomodachi ga Sukunai)

[Okano Hajime] I Want to Become a Girl (Who is a Boy) [English]

(C77) [Funikigumi (Yurikawa)] Otokonoko da toka Onnanoko da toka Sonna Koto wa Kankei Nai no desu! | Whether It's A Girl Or A Boy Is Something Irrelevant! (THE iDOLM@STER) [English] [4dawgz]

(C73) [Dasshifunnyuu (Nishi Iori)] RANDOM.BOY MEETS GIRL

[Distance] Shi Chau? - A cherry boy meets a busty girl (Wanna Do It?) [English] [Tadanohito] [Decensored]