When I was younger my mum told me that v* always came before d* when you have them together. Is this true or did she just tell me that to stop me worrying at the time? She told me that d* doesn't happen first, and if it does it means that you won't then go on to v*.

At the risk of sounding stupid, I have little rules in my head about v* that I made up when I was a child, and now sometimes I find it difficult to figure out what is real and what isn't.