Oh, FFS, Leady! How could you get it so wrong? It should be your *right* arse cheek if by GNSS, and *left* arse cheek if by DR/compass/whatever.
I'm embarrassed to realise I'd mixed up the northern and southern hemispheres. In the southern hemisphere the rule is, of course: "Scratchy lefty turning north and scratchy righty turning south."
Another important point made by AOTW. As you know, AOTW, the timing references are increasingly diverse and so it is increasingly important to include the reference in the broadcast. "By wristwatch/iPhone/iPad [with statement of IOS version] /Android [with statement of device and operating system version] / etc." That will determine which nostril I pick.