the degree to which one can successfully hover their asscheeks over and take a crap on top of the, by now, absolutely disgusting pile of shit that builds up in most port-a-potties on the closing days of a music festival or other widely attended event. not having your asscheeks touch the seat is a key concept of hoverability.
"good god, that port-a-john is disgusting. how the hell did you use that thing?"
"i've got good hoverability, bro."