The general idea behind this exercise is to help hosts who struggle to perceive their developed tulpa, may that be because of a stressful time or simply because they temporary lose their sense for it. However it can be used as a simple forcing exercise as well, but I would recommend to have at least a partly developed tulpa before trying it.
This exercise consists of three smaller and very different tasks, which are all meant to be done at the same time during the duration of the exercise. I recommend to practice each of this tasks alone until you have a general idea about how they work before trying to do them all at once. You should be able to do them semi-passive without them interfering each other, but it isn't necessary to master them beforehand.
If you struggle with handling this three tasks at once you have the option to start them up in phases. In this case you will start with the first task, and always add the next one as soon as you're really comfortable with keeping up the current maintained tasks.
This basic task aims at imagining every aspect of your tulpa without allowing any kind of feedback, like you would do during a regular day 1 forcing session. Visualize your tulpa and force every aspect of their personality you're aware of onto this image. Do this like you really want to burn this information inside your brain without questioning it. Like a programmed order you want to imprint on a soldiers mind.
The purpose of this task is to strengthen the existing image of your tulpa as a foundation.
This task is pretty much the opposite deal, and it can be tricky to keep both up at the same time. During this task you should try to calm yourself down to feel everything about your tulpa. Try to remember yourself about everything you're aware of about your tulpa. The visual appearance, the voice, every little trait or quirk, and even their way of thinking. Whenever you think about one of these aspects try to remember every detail of it, and how every of these details feels to you.
Try to receive these feelings coming from your tulpa, until you reach a complex impression of how your tulpa feels, as complex as it is possible for you. You shouldn't force any ideas on your tulpa in this task.
This task serves as the next level for perceiving your tulpa, building up on the second task. The first step of this task is to let yourself fade away. For this you simply need to calm yourself down, let all of your thoughts flow away without actively provoking any new thoughts. I recommend to use a calm environment for this. Personally I like to listen to quiet music during this task, but you should try out what really works best for you.
The next step of this task is to move your passive focus to your tulpa and away from your own mind. Back to its feelings and thoughts that you sense in the second task. You shouldn't try to think about this step, just stay aware that you want to do this and it will work out sooner or later. (At least if you can handle the second task). If your tulpa now tries to say something you should perceive it as clear and centered feedback inside your own mind. But again: Don't try to actively focus on any responses nor provoke them.
The summarized target of the exercise is to experience a well powered up and centered version of your tulpa. Responses should be clear, any kind of possession and/or imposition should work very clear and direct while you keep it up. (You can expand the exercise further for certain abilities if you wish too.)
Your tulpa should have an easier time interacting with you, even after you finished the exercise. If you feel that your tulpa starts to struggle again later on you can use the single tasks as a passive way to overcome it again, in any way it feels beneficial for you.