The self is "something that is having an experience", the "having" is in the "being a self". Self is like an extra category that got added on top of everything else going on experientially, a super-unity kind of memory, and a limit. The limit is functional as what falls within vs. outside of the limit, which translates into what we experience consciously and what unconsciously affects us. Becoming more self-aware means converting more unconsciousness into consciousness, but it also means becoming aware of how this conversion process poses limits to both consciousness and unconsciousness, which leads to inner laws as categorical differences within progressive self-awareness.
Forms of the self include all feelings, motive-inclinations and reactions, beliefs and cognitive sets, methods of reasoning and application of heuristics and algorithms, and memories. Memories are contents of consciousness that become forms of consciousness, that become forms to a given moment of consciousness. Methods of reasoning and application of heuristics and algorithms are hard-wired genetic or social tendencies to process information in certain ways, favoring certain values over others. Beliefs and cognitive sets are like memories, they are contents that become forms, only not merely memory contents but active vitalizing contents of the present moment of consciousness, an emergent combination of memory and methods of reasoning. Motive-inclinations and reactions are externalizing drives to act by locating the energy of conscious experiences and factors of experience and discharging it from those locations, causing it to immediately animate the body somehow. And lastly, feelings are collections of proprioceptive self-sensation of various physiological changes that occur in repeatable, stable patterns in the presence of certain stimuli, either physical stimuli, mental stimuli, abstract or ideal stimuli, real or imagined stimuli, including even stimuli we aren't even aware that we are present to.
Feelings are the closest to what we call emotions, since an emotion is a reconstitution of a chain of meaning with respect to feelings; feelings are not only collections of self-sensations of physiological changes occurring in repeatable, stable patterns but also include the further meaning that is attached to those feelings, what is technically not included in the feeling and acts as an external content to it, a content that can be variable from one person to another or from one moment to another in the same person. That external content is a phenomenology that is rooted socially-historically as pure meanings prescient to human being and as just the Fact of such meanings, which pure being of the meaningful is technically what we mean when we speak of emotions; emotions are this being plus the feelings (as defined above) that constitute the emotion in time and space. The emotion in space is the plurality of feelings structural to an emotion; the emotion in time is the relation between the spatial components and the phenomenological meaningful/Factual.
There is no "one self", the self is a bunch of various, fluid changing, and categorically different kinds of experiences, structures and tendencies that are all co-occurring together in a body. The mind is a crystallization of these sort of co-occurring aspects in the body coupled with relations to truths (meanings/Facts), while the self is a crystallization of those aspects, experiences, structures, etc. which are formative for the mind. Without a mind there is no self, without a body there is no mind.
The self is plural and multitudinous, hence why so much religion and psychopathology and philosophy are all focused on simplifying the self's self-experience as the many forms of the self seen in a narrower range than they actually exist in. The supposed value is to simplify things so that a "one self" is able to appear; this is faulty logic, since the self is never one self and is always "many", and it is always the case that this "many" is emergently producing a semblance of a One. One-ness is operational, derivative, illusory, and stabilizes the plurality of the many, but the one-ness can never replace the many, no matter how much Buddhist meditation one does, no matter now much insanity and sado-masochistic pain and criminality one engages in, and no matter how much Nietzsche one reads. The self is the self, and the many is the many, and the "one" is this "many is the many" and nothing besides. Therefore those above methods of attempting to simplify into one-existence the forms of the self are simply secondary consequences of the "one as the many as many" attempting to further self itself into existence out of its own plurality, which plurality it must end up dismissing and contradicting, resisting for the sake of an emergent self become "conscious" to itself. The conscious self that lacks understanding of the nature of the self and of the nature of the forms of the self is going to be driven by inclinations to resist and fight against its own plurality in order to stabilize its conscious image of itself, since that image lacks a more accurate understanding of what the self really is.
Every form of the self "orbits" every other form of the self; there is shared gravity; every "many of the many" in the self values others in terms of itself and self-values itself in terms of its relations to the others, thus can only indirectly self-value itself in terms of the whole of which it is a part. The whole does not exist in the same way that parts exist, therefore the parts are faced with a categorical limit beyond which they typically cannot pass. Each form gives gravity to the other forms to which it relates, and each form is pulled and pushed by each other form to which it has formed a relation. The idea of the will to power is here, but the true reality of the self is not located in the emergent will to power that appears and acts as if it were a One, but rather is the true reality in the forms of the self, in the constitutive experiences, perspectives, tendencies, feelings, aspects, forms, contents, bodies, histories, all of the smaller more singular entities that swirl together in collective orbit of self-relation in order to give rise, out of that activity, to the phenomenon of the self.
A lesson for philosophers, then: the self cannot dissolve itself in the forms out of which it is composed, since those forms cannot dissolve themselves in the self which they ultimately give rise to, for they give rise to it; neither can the self take possession of its forms and simplify itself into singular existence beyond the mandate of its forms, for the self is only the plurality of its forms and nothing besides. All attempts to either of these methods are merely psycho-philosophical methodologies of the phenomenology of what it means to be a self as the plurality of the forms of the self, the "many as many", and therefore such attempts are always secondary, partial, and act as limitations of the conditions out of which they come and which the act cannot know, as a kind of banality that seeks to live as pure error, which ultimately and always in the end is not possible.