Obviously an old Gaelic tradition for testing the shock absorbers... :-> Those young fellas in the first clip don't seem to have enough mileage on them to need to, but how and ever...
Regarding the mouth music, or lilting part of it - brings back to me a cassette I have somewhere of Joe Heaney (Seosaimh O hEanaí) where he tells an explanatory anecdote that leads into a lilted version of it. His rendition of the tune is 'Did-de-rum-do-di' rather than 'Hey ho, Diddly Do'.
His anecdote has a couple of tots of rum in it, needless to say.
It seems to be a tune that leads to levity on all fronts..