Narcissistic supply is a form of payment given by others in order to be in a relationship with a narcissist. In essence, when a young child is not sufficiently attuned to or attached with, emotionally soothed and protected, he develops self-protective survival skills. These survival skills come in the form of emotional manipulation and alternate-personality development. So yes they are aware of their requirements for supply to feel good but probably not aware its 'supply' as such. Just like you know you need to breath oxygen to stay alive the narcissist knows they need to manipulate, devalue and coerce to feel in control.