If you have a very recent model phone which has the Reverse Charging or PowerShare capability to wirelessly share it’s charge with other devices, then you should be able to use your phone to turn on EMO. You’d have to enable that charging feature on your phone, then hold it against his foot. Google your phone model or check with your phone manufacturer to see if you have this capability.
I haven’t been able to test this since I still have an old iPhone 6+. Although I see lots of conflicting information about whether it’s possible on ANY Apple iPhone at this point, and some websites say that Apple disabled it since it didn’t perform as well as expected?