The dipping of the wheel thing is only done (as far as I know) on cross country tours. The idea is that you dip your rear wheel into the ocean on one side of whatever country you're crossing ... and then you dip your front wheel into the ocean on the other side of the country once you've finished crossing. It's sort of a symbolic thing indicating that your bicycle spanned from ocean to ocean ... or some such thing.
I've never heard of it done on any tours other than cross country tours.
Do you ride with the Winnipeg Cycletouring Club?