inner-tubing
inner-tubing
n
(Swimming, Water Sports & Surfing) the sport of floating on rivers, rapids, etc using a large inflated inner tube as a buoyancy device
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014