They say it's because they can't "concentrate". It's really because they're fucking you based on a hedge. They're guessing that your status might be high enough, or that you might be a good provider. They're sure or desperate enough to take the chance, but they're uncertain.

They're worried your status might not be high enough, and that they should have waited for someone better. That's why they're distracted and can't concentrate.

Women are vultures in a ruthless and indifferent game of status and rank. It's their obsession. And funny enough, a lot of men don't hardly care about status at all.

I'm hard pressed to believe that even nerdy introvert girls don't care. At some point, to be turned on, something has to trigger their sexuality. And if it's female normative (not lesbian or something), then it will be turned on by notions of status or dominance.

Notice how some ladies don't get what would be unattractive about a transgender woman. They don't have an inborn worship of pussy, so they don't get it. Same with us guys. We don't fully grasp female eroticism. We can intellectualize it, but not experience it.