The mos tbasic idea about why magic is sexual is because it works with the union of opposites exactly as it happens in sex, nullifying the law of the principle of non-contradiction.
The principle of non-contradiction is subject to many types of logic, as it has long been considered the minimum guarantee of consistency for any statement or inference. According to the 15th-century cardinal, mathematician, and mystic Nicholas of Cusa, the coincidentia oppositorum—or "coincidence of opposites"—is the "least perfect" name for God. Nicholas of Cusa conceived of God as "coincidentia oppositorum," that is, the union of opposites.
This is an expression with a clearly metalogical meaning, which explains, in this philosopher's thought, why it is impossible to know "God" rationally. Nicholas Cusano gave the example of a circle: if it is expanded infinitely, all its components (diameter, radius, circumference) end up coinciding. Likewise, "God" is the point where all opposites coincide. In It, light and darkness, black and white, woman and man, substance and non-substance, are identical. "God," therefore, is also beyond the True and the False, since they coincide. The concept of Coincidentia Oppositorum subsequently influenced the work of numerous Western scholars, including Carl Jung, the founder of analytical psychology, who viewed the psyche of each individual as a coincidence of opposites—a blend of conscious and unconscious elements that together constitute a harmonious and unified whole called the "Self." This Higher Self represents the attainment of understanding and integration of the whole.
In magical practice, understood in the broadest sense, the so-called "coincidentia oppositorum" is a necessary condition for achieving what the ritual or practice was created to achieve. In other words, what happens with the construction of a magical ritual is that we create a contradiction on the material plane (temple, altar, gestures, weapons, breathing, visualizations), and elevate that contradiction to divine characteristics, with a balanced blend of all the elements that contribute to the celebration of creation. Then the Magician as God becomes the point where all opposites coincide.