My sister and my dad have this argument pretty often (which is ironic because she definitely got the behavior from him), and I was kind of at a loss as to how to mediate their conflict until I listened to this episode of the Mind Bod Adventure Pod where they advocate asking the person shaking their leg if you can join them, and then escalate motion until the need passes, and it actually works super well. It does kinda interrupt the conversation a bit, but I think most NT people are more bothered by the persistence, rather than the intensity, and are more willing to take a wiggle break than the constant monotony of vibration.