A minority sport that has many similarities to 'potholing'. Characterised by men with helmets squeezing into tight, damp spaces for the purposes of recreational exploration.
In the UK one of the best places to go potholing is in The Peak District where one of the most popular underground systems that can be explored is called "Giant's Hole."
It can be a risky sport, caves can flood and sudden attacks of claustrophobia can happen. Getting lost, or sustaining injury are concerns too.
In Southern England, the public toilets around the city of Brighton provide many good locations for buttholers to try out.
"Yo Tinkerbelle, before you go buttholing with your new boyfriend, tie a rope round yo'self for safety."