Understand that when we are talking about "energy" in the body it refers to a number of physiological functions that factor into our felt/sensed experience.
Have you ever had a rush of blood to your head and you get lightheaded? We could consider that a sort of sensation of "energy." When you drink a cup of coffee and your adrenals get going, that is a sort of "energetic" sensation, is it not? Or when you lift weights and your muscles feel pumped up. These are all commonly sensed, albeit mundane, experiences with a specific "energetic" quality. Another perfect example would be the orgasm.
I think one common trouble we can encounter when working with these "energy" practices is that we are looking for something extraordinary. When in fact these kind of practices are more about tuning into and refining our mundane and super-mundane senses, and with this developed awareness, directing our physiological systems toward harmony and balance. This is why Qi Gong is a whole system that ranges from diet and exercise to meditation, and even interior design. When one is talking about the "flow of energy" in a living quarter, they are really just talking about how the spatial function affects our spatial awareness and sense of presence, in a sort of spatial environment, a physiological proprioceptive feedback loop. When you rearrange your furniture in a manner that feels more harmonious towards your personal disposition and sense of space while baring in mind the certain laws and limitations of the physical environment around you and using them to your advantage, this could be considered a sort of practiced manipulation of "energy" that creates more balance and well being in your life.
When we are talking about "energy" in regards to meditative physical practices, like taichi or sexual kung fu, the key to understanding these concepts, experiencing them firsthand, and directing them with intention, is to understand "energy" as a supermundane experience that takes place at the intersection of body and mind. A sort of feedback interplay between our physiology and our sensed experience. The more you are able to refine your awareness to tune into what would otherwise only be extremely subtle sensations or internal experiences, the more those experiences and sensations will become palpable, and amplified. Basically, the feeling of "energy" is just about becoming more sensitive to more subtle sensations in our body and mind that tend to go unnoticed.
A foundational element of these practices is honing/sharpening/refining your awareness, and directing inward towards strata of experience that we tend to ignore. This ranges from the mundane yet somewhat conscious, to deep within the subconscious/ unconscious mind. You are training your mind to look under the hood and begin to recognize the natural functions and patterns of the interplay between our psychic and physical reality. At the deeper edges of our unconscious mind, we recognize our physical reality and the external experiences we navigate with our bodies, purely as symbols. Dynamic internal concepts and imagery, serve as a sort of interpretive data set of self-understanding. It could be said that the direct experience of this typically unconscious strata of the mind, is the experience of "energy" in its rawest form. Bear in mind that this is a stratum of mind that is inextricably interwoven with our physical reality. In fact, physical reality and mental reality are one and the same. What angle we experience these phenomenological realities from really just depends on where our awareness is directed, and what mental/physical functions we are approaching with. For example, dreams arise from our body and a number of physiological factors contribute to the generation of the dream experience. This is an experience that we typically have when relatively unconscious. However, we as humans also have the potential to access our dream functions in a conscious manner, through meditative practices that induce dream-related physiological functions and brain waves, while remaining conscious or semi-conscious. So, Mediative practices are designed to train the mind to access the different levels of awareness available to us, by inducing a spectrum of physical/psych conditions that exist on a spectrum. Direct experience of "energy" is really just a hypersensitive finely tuned awareness of our everyday mundane reality. The deeper we dive into the dimensions of the mundane the more amplified and expansive the experience of the mundane phenomena becomes.
"Energy" is not something you are not already experiencing on some level. It is just a matter of how you are consciously accessing that experience. We live in a society where so much of our experience is externalized. Our awareness is constantly being pulled outside of self, and it becomes increasingly difficult to access more subtle dimensions because we are numb to them from endless external stimulation. It can be very difficult to tune into our internal sense of reality and trust the experiences we are having. The best way to access deeper supermundane strata of mind and body is to continually come back to mindfully intentional practice which allows the natural order of things to reveal itself to you. This means coming back to the practice every day, and slowly peeling back the layers of the onion. Know that there is no right or wrong experience, just experience. Seek to understand, through observation what your experiences could mean for your mental/physical system as a whole. Observation is key. Awareness is what will guide you. While there is plenty of great technical information available on these practices (and it is crucial we study those who have traversed the terrain before us, for insight and knowledge), understand that this information is only the map and that ultimately you will have to traverse the terrain yourself. There can be times when the whole thing feels impenetrable or dumbfounding. Our body and mind can be a real labyrinth sometimes, and knowing which direction to head in can be really challenging. This is when you have to trust your own deeper wisdom. Trust that your body and mind have the answers you seek. They are ultimately who will teach you what you need to know. Our body and mind already know the path toward balance and harmony, we need only listen. With intentional practice, over time you will come to be able to trust your own experience more.
So in terms of feeling "energy" just practice awareness every day. Turn your attention inward and see how deeply you can relax into yourself. Allow what you already know (on some level) to reveal itself to you. All the various mediative/physical traditions of practice are mere tools for accessing what is already available to us. Each practice has its own merit, but ultimately it is about how you approach the practice. Approach with an open yet focused mind, and trust your own inner compass. You'll be a super sayain in no time.
From what I understand you have gotten pretty good at the pumping mechanism at your pelvic floor, being able to withhold orgasm, and even having multiple orgasms in a row. This is definitely an important mechanism to hone in sexual kung fu, and no easy feat so congrats on the accomplishment. However,
it is crucial to remember that too much tension in your groin, and a hyper-focus on this one mechanism can lead to pathologies of its own. It is crucial to think of the practice as holistic. For one, make sure the pumping at your pelvic floor is a gentle pumping that is integrated into the whole structure of your body. Do not create hypertension in this area. Remember that there are many other mechanisms at play in this practice that are all working in unison with an integrated holistic body system. The pelvic pump is just one piece of the whole picture.
In general, I would say it is probably wise to not get hyper-focused on the sexual aspect of this practice, and understand that is a practice to be integrated into a larger system of practices. Focus on other forms of opening up/integrating your body and mind as well. The more you have a well-rounded practice the easier it will be to incorporate your sexual practice in with success and balance. Do other restorative practices like yoga or chi gong, as well as breathing exercises, diet, and more external exercises like weight lifting or calisthenics. The more your body is open, integrated, aligned, and working as a whole system, the easier it will be to draw orgasmic "energy" upward and circulate it through your entire system in a balanced manner.
Personally, the practices I keep returning to and find the most depth in are qi gong silk reeling exercises, taichi, bagua, some yoga poses, Taoist breathing exercises, wim hof breathing, and calisthenics. Above all though I have had the most breakthroughs with tree post-standing exercises, in terms of opening and aligning my body with gravity and tapping into the natural rhythms and cycles of my physiology. I have outlined a number of these practices
here in this post if you want a starting point to explore these concepts. You, of course, will find your own routine and the exercises that work best for you and that is just a matter of experimenting and over time cultivating what works best for you.
To address directly your question about moving "energy" up your spine, I would recommend (other than the practices I have mentioned above) you spend time with the sitting meditation/microcosmic orbit as I outline it
in this post. For now, rather than focusing on drawing the energy upwards, just learn to tap into the natural rhythms and sensations of your body in the sitting position. Review all of the basic alignments I outlined, and key points on the body, and see if you can sense how they are all relating to one another. Review the other pumping mechanism I outline that aid in successfully drawing energy up your spine, not just the pelvic pumping. Read closely my suggestions on how to move your awareness through your body, and practice this meditation regularly until you feel like you are beginning to have a personal understanding of it through your own felt experience. See if how deeply you can sense into your body, Can you feel your organs? Does each organ have a unique sensational quality to it? How about all the way into the core of your bone marrow? Can you feel that deeply? What sort of brainwaves and mental states are you accessing when you feel that deeply? How relaxed do you have to be to feel that deeply? How alert do you have to be? As I said before, trust your intuition on this, it will all come together in time. Once you are more in tune with these natural rhythms and the pumping in your spine in relation to your connection to the earth, it will become more simple to direct more dense sensational experiences like an orgasm upward.
One small tip I can give you here for drawing energy upward is that where the mind goes energy follows. So if you are focused too much on the pelvic pump the energy is sure to stay in that region. Learn to create a relaxed clear channel through your whole body and directed your mind upward. The pelvic pump is just there to hand off orgasmic energy to the other channels in the body. You are not forcing things upward, but rather gently and intentionally guiding. The mind is the key driving factor though. Focus where you want the energy to go, rather than where you are directly experiencing it most intensely (in your genitals)
And lastly remember this is a lifelong practice that will only deepen more and more, so just take it one moment at a time and don't get too ahead of yourself. It is good to have an end goal in mind, but that might not actually look exactly like you think it does. So slow and steady. Planting one seed in the garden at a time.