Please allow me to explain what a body map is. Many are familiar with the concept of an amputee having the feeling of where the toes or fingers of their missing limb are, and feeling as if the missing limb is present.
When some FTMs stand before the mirror and as they relax, they can see the outline of their male body, such as how tall they are, the thickness of their arms and legs, how broad their chest is, the features of their face and the shape of their privates. They can also tell how muscular they are.
Likewise, some MTFs can stand before the mirror, they can sense how tall their female self is, the bone structure of their face, the size of their breasts, etc.
In my opinion, this is not the product of fantasy, but the observation of their true gender, just as a person who has lost a limb can not only sense the limb that is not there, but the location and what the limb looks like.
Feel strongly this exercise before the full-length mirror, if at all possible, but the bathroom mirror will do; and making every effort to replicate what is seen as the true gender, will create the best closure.