I felt that Kingdom works were a bit lacking so I I'd scour Pixiv. I don't speak Japanese so I just machine translated the title.

https://www.pixiv.net/en/artworks/48730010 and https://www.pixiv.net/en/artworks/48956631

バレンタイン～ホワイトデーの期間に合わせてみました、いつかやってみたかった毅恬。（※賁恬前提です）
ちょうど元旦にツイッターで妄想ネタ呟いていたら、つむじさんにリク頂きまして、せっかくだから漫画にしなきゃな、と。その節はありがとうございましたｗ
蒙毅開眼注意。

前編はこちらillust/48730010
蒙毅の帽子しぬ程めんどくさいので脱がしましたがポニテで良いんでしょうか？
小さい時と同じくお団子+はみ出し毛にしようかなと迷ったんですが、どっちにしろ帽子の中で納まるものなのか…
あの丸いとこに収めてるのか…本当に謎なので設定資料ください。

(machine translated)
I tried it to coincide with the period from Valentine's Day to White Day, and it's something I've always wanted to try. (*This is based on the premise)
Just on New Year's Day, I was tweeting about my fantasies on Twitter, and Tsumuji-san asked me for it, and I thought I should turn it into a manga. Thank you for that section lol
Meng Yi eyes open beware.

It was too troublesome to wear Meng Yi's hat, so I took it off, but is it okay to wear a ponytail?
Like when I was little, I was wondering if I should wear it in a bun or with the hair sticking out, but I was wondering if it would fit inside the hat either way...
Is it stored in that round place? It's really a mystery, so please give me the setting information.