From Divinity Engine Wiki
- query ItemCanSitOn([in](ITEMGUID)_Item, [out](INTEGER)_Bool)
Returns whether _Item is can be sat/lied on, or a character can be constrained to it.
- Success/Failure: Default return value.
- _Bool: 1 if the item has at least one of the following use actions: sit, lie, or constrain; 0 in other cases.
- This query returns 1 even if someone else is already occupying the item and there is no room for another character to "sit" on it, or if the item was marked as non-interactable.