Supertenko (スッパテンコー, Suppatenkō), also called Suppatenko, is a Touhou Project themed variant of the “Ainabridge Taisa” kopipe, which was first posted on September 12, 2003 within the Touhou Series General Thread in 2channel's /gsaloon/ board on September 12, 2003.¹⁾

The original story is about a man caught loudly masturbating while using the family computer by his younger sister,²⁾ but in this variant, it's about Ran Yakumo who was caught using her spell cards naked by Chen. As for the name, it's a portmanteau of Ran's “Shikigami's Radiance 「Princess Tenko -Illusion-」” spell card with the “Super Onanie” phrase from the original story.

マヨヒガには部屋がふたつしかありません。みんなでつかってます。
で、ご主人様と橙が大抵家にいるのでﾃﾝｺｰした事がなかったです。
しかーし、起きると二人ともいない！ラッキー！ﾃﾝｺｰできる！っと喜ぶ暇も惜しんで、となりの部屋へ！
当然式神らしく下半身スッパﾃﾝｺｰだ！
ああ、、、ブディスト、四面楚歌楽しいよお、などとお気に入りスペルで盛り上がる私
そして、いよいよ大詰めが近づき、フィニッシュに選んだのはやっぱりﾃﾝｺｰ！
もうテンション上がる事山の如しで、ほとんどブリッジ状態でワープしまくり！
誰もいないので、「ああ～！テンコ！テンコオオオ、プリンセスたのしーよーーー！たのし～！」
等とほぼ絶叫しながら逝こうとしていたとき、、、、
「藍様、うるさい～」と笑いながら黒猫の式が入ってきました。
私は宴の準備等で大声を上げることが多いので、そんな感じだとおもったみたいです。
しかしそこには、下半身裸でイリュージョンしてるマスターの姿が、、、
飛翔毘沙門天で部屋を出て行きました。ご主人様がかえって来るまで、となりの部屋から出てきませんでした。
２週間会話してないです。。。
以前は尻尾の中でお昼寝させるほど仲の良い式神だったのに、、、
憑きたてほやほやなのを嬉しそうに話してきてくれたのに、、
すまん、マスターは変態なのだ。。。

どうしたらいいのでしょう？？
だれか、もっと恥ずかしい話をめぐんでください。。。

There are only two rooms in Mayohiga and everyone uses them.
My master and Chen were usually at home, so I have never tenko'd.³⁾
But if you wake up early, neither are up! Lucky! I can tenko! No time to rejoice, to the other room!
Naturally, with the lower half of my shinkigami body, I could Super Tenko!
Aah,,, Buddhist,⁴⁾ Siege from All Sides⁵⁾ is fun, etc. I got erect from my favorite spell cards.
And then, for the grand finale, I chose to finish with Tenko!
The tension of the mountain has risen up, it was like warping a bridge!
Nobody was up, so I yelled “Aa~! Tenko! Princess Tenko~, I feel good~! So good~!”
And so on. While I was screaming and almost ready to ejaculate,,,
A black cat came in and laughed, “Ran-sama, so noisy~”
Since I usually yell when preparing a party, I thought I could pass it off as that.
However, you could clearly see her master performing illusion while her lower half was nude,,,
I left the room with Flying Bishamouten.⁶⁾ I wouldn't leave the other room unless my master came.
For two weeks, I didn't speak…
Back then, I was close to my shikigami and would let her nap in my tail,,,
She would happily talk to me while I possessed her,,
I'm sorry, your master is a pervert…

What do you think I should do??
Someone, please share a more embarrassing story…

• It's fine to associate “Supertenko” with a nude Ran since the original story is rather obscure, but do note that it's over a decade old and might make some people cringe.
• Tenshi Hinanawi, sometimes dubbed “Tenko” by fans, did not exist when this was made.

• Supertenko on Niconico Encyclopedia
• Touhou Thread Glossary (Sa Line) § Supertenko on the Japanese Touhou Wiki