wagecuck -> working stiff
when you can no longer maintain an erection -> when you are past the prime of your life
With these simple substitutions you can once again sound like a reasonable human being who is not overly fixated on unnecessary crude sexual imagery.
Considering that we're discussing a Bukowski letter (who was "overly fixated on unnecessary crude sexual imagery" and proud of it), this is not necessarily advisable.
It sounds like a suggestion for the parent to "empty out" and adopt the officially tolerated sensitivity/language, lest some office drones be outraged.