Currently browsing Amazon Japan sextoy category, and...
Despite selecting "Prime eligible only", there are

SO MANY
AMAZING
AND
WACKY
PRODUCTS

since kouhai wants examples:

You know about the thumbscrew, a torture device? Well:
https://www.amazon.co.jp/乳首クリップ-ニップルクリップ-おもちゃステンレススチール製-アダルトグッズ-2個セット/dp/B07DVG3B6F/

urethral probe? yeah sure. and VIBRATING 😈
https://www.amazon.co.jp/尿道プラグ-10つモード尿道バイブ-亀頭マッサージ-電動シリコンピック-シリコーン製/dp/B07K6J538Y/

ENLARGE YOUR PENIS!
(or force down an unwanted erection, I'm not sure..)
https://www.amazon.co.jp/URAKU-ペニストレ器具-ペニスエクステンダー-大人のおもちゃ-ペニストレーニング/dp/B07JG1VN1D/

Kawaii nipple suckers!!!
https://www.amazon.co.jp/振動＋吸引-乳首ローター-おっぱい刺激-SMプレイ-10種類振動モード/dp/B07HQDWH1Y/

I think some of you are pure and innocent enough to not know the stuff Tamatoys sells, so:

perfume of black stockings, for all your class iinchou fantasies

https://www.amazon.co.jp/Tamatoys-タマトイズ-TMT-848-女子校生の黒ストッキングの匂い/dp/B0711LNM2L/