From Tulpa.info wiki

A Tulpamancer is a term used in the tulpa community to refer to the individual who engages in the practice of creating Tulpas, known as Tulpamancy. Although generally a Tulpamancer was a Singlet before they began Tulpamancy, there are cases of individuals who are already Plural partaking, in which case the Tulpamancer may not be the Host.