All metaphysics are based on assumptions that require belief—a feeling of certainty—without ultimate scientific proof. For Kreutz Metaphysics, this is the assumption that engaging in optimal sex generates and develops a human soul that emanates from physical human existence and persists beyond the physical lifespan.
Wilhelm Reich formulated a vaguely similar concept, but with only science in mind and no religious inclinations.
There is obviously not much experimental proof for this premise, though scientific multiverse theory does make it plausible.
But mind you, other metaphysical systems are far less scientific than Kreutz Metaphysics. As a matter of fact, if you study in detail what other metaphysical systems teach their followers from a scientifically oriented perspective, you will be astonished by the sheer nonsense they hold as dogma. Kreutz Metaphysics, at least, makes sense.
Metaphysics can be discussed and criticized from various perspectives. One is a utilitarian perspective derived from John Stuart Mill, which suggests that the literal truth of a metaphysical system matters less than its utility. It only matters to what extent it provides happiness, or pleasure, to its believers in the here and now.
And in that domain, no other metaphysical system can top Kreutz Metaphysics.
No asceticism is required. Engage in optimal sexual intercourse, and rest assured that this is in line with the commandments of Kreutz Metaphysics, and that it is, in fact, a religious service to secure your immortal soul.