[jimnotgym]

I wasn't conflating two things, it appears my stress relieval procedure has more steps than yours. For your part 2 (in addition to what you said for part 1) I also used to grab the wheel with one side against my belly, forarms across the rim edge, so elbows at 3 and 9 oclock and hands at 12. Then I would push my elbows down to get the pinging sound you described, and then rotate a quarter turn and repeat. Then turn over and do the same. When it stopped I would retrue the wheel and do it again. If you don't do this you get the pinging you described on your first ride and a therefore a wonky wheel.

I believe this is one of the important steps in making a wheel stay true and not need trueing after one ride. This is described better in the Art of Wheelbuilding if you want to try it.