When visiting a large sculpture, building, or structure of some sort you take a picture while positioning yourself where your dick in comparison looks the same size or larger.
I've collected dickscapes of myself around the world, the Leaning Tower of Pisa, CN Tower, and even the Burj Khalifa.
In some cultures, the art of shaking someone's dick when being introduced or meeting them for the first time. Note: It is also rude to shake very limply.