John had had sex but never with another human being. That's about as delicately as we can put it. Though he'd been weathered not to bother responding to a direct statement from a female directed to him, he couldn't help but recognize an opportunity that most men just don't get in a lifetime.

He had a girl up in a tree who needed his help.

With a natural inclination for empathy with those in worse situations than he considered his own to be, and with the bonus of her being fairly dependent upon him, he decided to see where this went.