上句见：Day258
The Story of Philosophy《哲学的故事》第1章Plato第4节IV. The Ethical Problem第4段引文第3句：

This, of course, is the doctrine which our own day more or less correctly associates with the name of Nietzsche. "Verily I laughed many a time over the weaklings who thought themselves good because they had lame paws."11 Stirner expressed the idea briefly when he said that "a handful of might is better than a bagful of right." Perhaps nowhere in the history of philosophy is the doctrine better formulated than by Plato himself in another dialogue, Gorgias (483 f), where the Sophist Calicoes denounces morality as an invention of the weak to neutralize the strength of the strong.
They distribute praise and censure with a view to their own interests; they say that dishonesty is shameful and unjust — meaning by dishonesty the desire to have more than their neighbors; for knowing their own inferiority, they would be only too glad to have equality…. But if there were a man who had sufficient force [enter the Superman], he would shake off and break through and escape from all this; he would trample under foot all our formulas and spells and charms, and our laws, that sin against nature…. He who would truly live ought to allow his desires to wax to the uttermost; but when they have grown to their greatest he should have courage and intelligence to minister to them, and to satisfy all his longings. And this I affirm to be natural justice and nobility. But the many cannot do this; and therefore they blame such persons, because they are ashamed of their own inability, which they desire to conceal; and hence they call intemperance base…. They enslave the nobler natures, and they praise justice only because they are cowards.
11Thus Spake Zarathustra, New York, 1906, P.166
浙江大学译本：一个真正会生活的人能将他的欲望充分发挥和表现出来，但当这些欲望增长到最大限度时，他又能用勇气和智慧来调控它们，并同时满足他所有的渴望。

解析

1、He who would truly live ought to allow his desires to wax to the uttermost;
一个真正会生活的人应该允许自己的欲望心情滋长。
wax: to become larger or more; to increase in amount, size, etc；增大
Meanwhile the comet had waxed to its largest dimensions, — so large that not only the nucleus but a portion of the tail had been visible in broad day.与此同时，这颗彗星的尺寸已经达到最大——大到不仅可以在白天看到彗核，还可以看到彗尾的一部分。《塔中恋人》
uttermost: of the greatest possible degree or extent or intensity 极度的；极端的；最远的；最高的
Here surely the victory had come in time, the climax had been scheduled with the uttermost celestial foresight.毫无疑问，胜利来得正是时候，高潮的到来已经有了最远大的先见之明。《美丽与毁灭》

2、but when they have grown to their greatest he should have courage and intelligence to minister to them, and to satisfy all his longings.
而当欲望膨胀到极致时时，他应该有勇气及智慧来帮助它们，并满足自己所有的渴望。
minister to (someone or something): to help or care for (someone or something)满足（……的需要）；服侍；帮助
We want a recreation in adulthood of what it felt like to be ministered to and indulged.我们希望在成年后重新体验被照顾和沉迷的感觉。《社会关系学》
longing: a strong desire for something or someone逃亡；热望；憧憬；
It takes kindness to oneself to interrupt the longing for suffering and anguish.只有善待自己，才能戒断对痛苦和苦恼的渴望。

这句继续讲述超人的生活。不控制欲望，用勇气与智慧来帮助它们，从而满足自己所有的渴望。

真正会生活的人应该让自己的欲望尽情滋长；而当欲望膨胀到极致时，他应该有勇气及智慧来帮助它们，并满足自己所有的渴望。