Is there any extension to control the power of the vibration so that it can run at 50% percent power so it's not full blast for as long as you want it?
you could search the extensions directory App Inventor Extensions | Pura Vida Apps
for example
- VibraCycle Extension]([FREE] VibraCycle extension - Extensions - Kodular Community) by 11119 to expand the possibilities of vibration
Taifun