ShampooChallenge シャンプーチャレンジ
A real-life photo challenge where a man is shown balancing a [[shampoo bottle]] on their [[bulge]]. While the challenge is similar to common [[penis]] length comparisons with items such as soda cans or pipes, it instead measures how sturdy the in-underwear [[erection]] is to properly carry a small item.

h4. See also
* [[tawawa challenge]]
* [[bubble tea challenge]]
* [[tag group:meme]]
shampoo challenge