Okay, this is probably off-topic, but I'll give it a go.
Lex can write some pretty hot stuff, but he's got the 'let's push too far' thing down to a science. A story he's still adding chapters to started very well (and deserved the high ratings it got), but has now degenerated into a laundry list of near-death experiences. In the example you gave, what leaped out at me was the impossibility of it. Birth control pills keep an egg from being released from an ovary. It doesn't matter how much (many?) sperm she's subjected to, if there's no egg for them to attack, she's not getting pregnant. And as for a 'bastard' surviving several abortions...let's just say that Lex doesn't write stories that are set in my world.
Having said all of that, though, I believe that what was intended to be erotic in the quoted passage is the humiliation Joyce feels from being used as a repeated practice dummy and from attending class with the message written on her tummy. Lex's stories tend to focus on wiping away a woman's personality, usually through a combination of physical and psycological overload, repeated endlessly. I don't think the abortions were intended to be erotic, I think the effect of the abortions on Joyce was intended to be an element in a (hopefully) erotic assault.
Be nice to know what Lex thinks.