@Drew, thank you!
If anyone else is interested, here's a code snippet to demonstrate a vibration on your watch:
Add the following line to your AndroidManifest.xml:
In your code:
Vibrator vibrator = (Vibrator) getSystemService(VIBRATOR_SERVICE);
long[] vibrationPattern = {0, 500, 50, 300};
//-1 - don't repeat
final int indexInPatternToRepeat = -1;
vibrator.vibrate(vibrationPattern, indexInPatternToRepeat);