Geryon's sexual development

Geryon’s first encounter with sex is his brother abusing him. They develop an “economy of sex” (28), Geryon getting marbles for “allowing” his brother access to his body. But he does not just do it for the marbles or because of the pressure, he also thinks: “Pulling the stick makes my brother happy” (28).
This notion of sex as something you do for the sake of someone else stays with him in his relationship with Herakles. At first he does not want to have sex with Herakles, but he knows that he will lose him if he does not. In the chapter right after their conversation about sex we get the sentence: “SPIRIT RULES SECRETLY ALONE THE BODY ACHIEVES NOTHING” (46), that Geryon and Herakles paint on a wall two years later. But if we keep in mind what has happened in the chapter before, we can connect this sentence to Geryon’s sexual experience. For sex to be enjoyable, you need body and mind, and probably Geryon is not yet able to engage mentally in sex. He just “lends” his body to Herakles because he feels it is something he owes him.
This is emphasized in the next chapter, “Lava”, where Geryon has this strange vision of being a woman waiting for her rapist to come up the stairs. In “Somnambula”, the following chapter, Geryon watches two butterflies procreating, and he observes: “How nice, (…) he’s helping him” (49).
A change takes place in “Grooming”, when Geryon finally satisfies Herakles orally:

“Geryon felt clear and powerful – not some wounded angel after all
but a magnetic person like Matisse
or Charlie Parker!” (54)

In this instance, Geryon is finally able to take an active part in their relationship, and by doing so he starts feeling more powerful and in charge of his own sexuality.
But right in the next chapter Geryon paints a “red-winged LOVESLAVE on the garage of the priest’s house” (55), showing that overcoming his abuse will need a lot more time. But Herakles cannot understand that:

“All your designs are about captivity, it depresses me.
Geryon watched the top of Herakles’ head
and felt his limits returning. Nothing to say. Nothing. He looked at this fact
in mild surprise.” (55)

Apparently Herakles is not the right person to help him overcome his negative feelings about his sexuality. Herakles seems to understand that, too, and soon breaks up with Geryon to move on to someone with whom he can enjoy sex more freely.