Horse paws while standing still when riding?

So, I have a 4 year old gelding who started this today. He tends to paw when he gets bored but typically it's during baths or if he's tied up. He's gotten better on the ground because I've made him stop. But today, after warming up at the walk, I asked him to whoa and stand still because it's something he doesn't like to do. 3 seconds after I stopped him, he started pawing out. I pulled back on the rein and squeezed him with the leg on that side while telling him to quit. He stopped but I don't know if this was the right correction. What should I do to get him to stop pawing, in case he does it again?