Self As Understood Conscious Experiencer
Obviously the acronym was chosen after the fact made to match Dennett's epithet that other philosophers reject his model and his expositions of consciousness as leaving out the magic "sauce" of "real" consciousness.
It of course refers to the notion that "self" as we perceive ourselves is that which experiences our sensations and drives our consciousness. But that leads to the obvious recursive problem of the Cartesian theater. Likewise there are now myriads of documented experiments demonstrating the initiation of something that will be perceived in consciousness well before (minimally about 400 milliseconds, but in some instances ... ex Damasio ... as long as seven seconds) the subject knows what his perception or choice will be.
The reality of course is that the real perceiver is the physical brain and the processes it enacts. Brains as bags of biology as partitioned groups of chemistry manifesting the physics we understand don't do "perceiving". They do chemistry and physical interactions. "Perceiving" then is a change in physical state which affects the later interactions of physical process. In the words the "disposition" of the brain to future events. But of course this leaves the magic "sauce" out. But on the flip side, the reality side of the table, given a complex enough matrix of interactions and potential dispositive changes reasonably well organized and we have, by the time we get to human brains, and incredibly complex Turing engine and these dispositions thus statements of representation and information.
So the SAUCE is actually a physical representation within the brain. And the notion of SAUCE as the perceptant of experiences is also a representation.
The SAUCE is quite real .... as a structure of how the brain does things, as a representation of its own processing. But at the same time that it - the representation, rather than the brain which genuinely perceives (as chemistry) and acts (as chemistry and physics) - is completely and unquestonably false.
Self versus SAUCE is the pivot of the dualists' claims.