Possession or Switching π±
People who make a Tulpa π±, with enough time and effort can get to the point where they can do something called 'Switching'.
This is where the host and the Tulpa can switch placed with each other, allowing the Tulpa to control the body for a short time.
There are many different forms this can take though, with different levels of control for each party.
Some have experienced both the host and the Tulpa working together to control the body, others have experienced a blackout where the host will become unconscious or feel like they are in a trance during the switching.
Backlinks:
Sources:
Tulpa Switching Experiences Study - Conclusions
Data from above study
Notes: