I got a large aerosol can of Dynax s50 which comes with a long thin plastic tube with the spray vents round the end. Just thread it in through the various holes in the tubes and spray as you draw it back out. Best to stop spraying just before the tube comes right out otherwise it gets even messier than it needs to be. I'm sure there are many equivalent waxes about, all with similar marketing claims.
Have done it body on and body off. Easier body off but not that great a problem either way. You might want a good supply of clean rags, brake cleaner, gloves and old clothes!
