Day taken off work with the intention of bashing one's bishop. Often the real reason behind a collegue's claim that they're "working from home".
A: "Is Mouldy in today?"
B: "No, he's working from home."
A: "Oh aye, having a moist day is he?"
B: "I reckon so."
A: "Fuck my boots, he must be dry as the Gobi desert."