In concertos, I stand up, and I conduct with the bow when I'm not playing. During symphonies, I sit, but sometimes I stop playing to conduct. Being seated in a section allows me to feel more like we're playing chamber music, which is how I like to approach it.
The great secret is that an orchestra can actually play without a conductor at all. Of course, a great conductor will have a concept and will help them play together and unify them. But there are conductors that actually inhibit the players from playing with each other properly.
I always have loved the Stradivarius. My teacher, Josef Gingold, he had a Stradivarius. As a treat, he would put it under my chin and let me play a few notes, and I remember that feeling of the overtones, the complexity of the sound. It's like a great wine.