Am I the only person who thought he was asking if moon ing the other driver was brandishing?
To be clear, in Texas you could have been prosecuted for brandishing. You had no claim to self defense here, and you intentionally did it.
Also lets be frank. It wasn't a very smart move.
1. You should have moved off from the situation.
2. I never had a bike that couldn't leave a car in the dust as an afterthought.
3. Showing a gun on a bike when he has a two ton vehicle that can smear you if that was his intent was..inprudent.