(Do I need to give a spoiler warning for a movie that is over 75 years old?!)
In Dumbo, the little elephant with big ears is given a magic feather to help him fly, and off he goes. When he loses it he suddenly believes he will crash! Thankfully his good friend tells him he could fly all along: the feather was just something that gave him the confidence to do it.
And with that he flies again.
If you’ve done the research, written a thesis and submitted it, you don’t need a magic feather for the viva. You’re supposed to be there, you have the talent. If you have a ritual, be it three coffees or good day socks, and that helps, then do it – use whatever confidence you can find.
You don’t need one, but if a magic feather will help then get looking.