In my mind, when you "park" you hold the tiller and adjust the rudders to keep the boat "parked" - its Rick's technique, main out, travelor out, etc. The point being that the tillers not lashed, its free to be adjusted. It might be under your leg, but you can move it.

Its something you do right before a race or after a race, or while you are waiting and dont want to move. You are "parked"

Heave to is different. Heave to, is tiller lashed, riding out the storm, kind of thing.

I'm not convinced the heave to that Gary described will work or is safe, or good for your sails.

Bill