The point where one cannot hold her their bowel movement, typically diarhea. The body stiffens up like a wooden board, hence the name 'boarding'.

Quick movements while boarding may cause one to shit their pants. Famously discussed by former Dodger's pitcher George Brett regarding an incident of food poisoning in the Las Vegas strip.

planking but face up, laying flat on top of, across various objects face up

See docking. But with more smegma...more...a little more...woe! TOO MUCH!!!