Adding a vibration motor

[Newchair2644]

Hi, I was looking into this project and think its amazing how open everything is to be modified by anyone! Wondering if there are pins on the back that can be used for a small vibration motor. If not, can it be done with some careful soldering directly to the esp module? I would modify the pcb but do not know how... I apologize in advance if this is not the appropriate place to ask!