Al shrugged, eyeing the ceilings. He didn't apply Expanding charms to them yet, and they could probably provide double the volume of the original room if charmed properly. He thought of sofa and coffee table around an upside-down candelabra sticking out of the ceiling like a tree and the idea didn't seem too bad. It could be charmed to be hidden more easily than the furniture along regular walls which received more surveillance, or hidden completely, or disguised as a ceiling painting, an Escher-esque second room within room one could enter only by somersaulting up and defying gravity.
He smiled as his hand found Severus'.
"Something that responds well to permanent sticking charms and doesn't look too out of place hanging upside down, perhaps."