Approved, Guides (preferably), although it could also work in Tips, even if I think this is a sufficiently essential technique to count as a Guide.
This is an essential communication technique and mindset. I'm not aware of many guides which address this, despite its importance.
It's a little bit of mindfulness meditation which is very "light" and at the same time slightly focused on any part of your virtual (imaginary) senses that you wish to perceive, and usually also 'focused' on the tulpa('s essence) - or more precisely you become "open" to perceive thoughts they're sending you without yourself interfering with what they're sending you, while at the same time also being free to think your own personal thoughts without interrupting the tulpas thoughts/emotions/senses that they're sending towards you.
As Sands mentioned, it's a very common mental state to be in when communicating with your tulpa, but at the same time, it's not something I had an easy time figuring out right away when I first read this guide - figuring it out for me was more of a lucky accident while meditating/doing self-hypnosis, rather than anything else.
All the symbolism in this guide isn't very necessary - achieving this mental state is very simple once you get a taste of it for the first time and know to recognize it (which may be a bit of a problem for someone just starting out and not knowing their bearings).