Noble sexual display involves socially acceptable, clean, and non-derivative displays of sexuality. For example, when a woman tastefully presents her breasts or mouth toward a prospective mate.
It's associated with European culture, and proclivity to admire actual sexual organs, which butts are not. The opposite of noble sexual display is callous sexual display
Noble sex is only for males who already have access to a vagina and do not need to forcefully come through the back door. The most common reverse lordotic postures include a woman topping a man, or a man entering during front-facing missionary intercourse.
The pose is also meant to encourage and facilitate intimacy, which is necessary for long-term pairbonding, and slow-life strategists.
"Reverse lordosis" is a female ornament used to keep high-status men around her, long-term, while she impregnates herself.