I didn't say anything. Delicate situation as it is and he was already sulking about something else so I didn't want to escalate things.
But, rather than sit on the comfy corner bit of the (18-month-old) sofa he sat awkwardly on the small awkward chair next to it and used the sofa instead to put his tobacco, papers, assorted other stuff and his plate and knife on top which had been used for cheese and biscuits. I moved this to the table but it appeared again.
Is this an OK thing to do or am I right in thinking it's a bit gross and not really good guest behaviour?