Friendly Questions
Around submission time reach out to your friends and colleagues in your department.
For the particular friends who might know a little about your research, ask for time: can they listen to you talk about your work? Would they have an hour in their schedule to get coffee and give you a mini-viva? Or perhaps get a group together and listen to a seminar?
For friends and colleagues who have had their viva, ask for information: what was their viva like? What happened? How did they feel? Consider what you might need to know about to help you get a good sense of what vivas are like or to put your mind at ease. Ask for details.
Who do you know who could help you?