Negating form does not mean denying it. It is quite the opposite of denial. Negating form means not identifying with anything as outside of you, or separate from you. It is the deepest form of intimacy. 

The experience that one dwells within all form as formlessness is the very nature of non duality. How could we be just one tiny separate part of this vast experience? Really try and experience everything as the same in this moment now. Tell me where the end of "you" begins? How can there be a beginning and end of you? Of anything? 

There is only a beginning and end of form. Form is constantly changing. Form is impermanent. The essence of form is formlessness and it is this essence that is indwelling all existence.