Raise-to-speak is the answer here. It's guaranteed to go to your watch, without all the device-negotiation that saying "Siri" causes: so long as you don't say "

Raise-to-speak is the answer here. It's guaranteed to go to your watch, without all the device-negotiation that saying "Siri" causes: so long as you don't say "Siri", it'll be unambiguously on the watch. That said, very annoyingly, WatchOS 10 seems to have regressed the raise-to-speak behavior, and it's being super-finicky for me. I've had to retry a lot of times, and had to fall back on long-pressing the crown sometimes, which reacts really slowly now when this is happening. (I think this might be it trying to negotiate microphone usage with my AirPods when I'm wearing them or suchlike, in which case Apple needs to stop doing that.)