I woke up with this scene in my head. I found it kind of insightful:
~.~.~
She rubbed her fingers over the head of his cock, eliciting a long sigh. Her fingers still moving lightly, she looked up at him. "So this is the part of the penis that most responds to stimulus?"
"No," he said. He used two fingers to point emphatically to his eyes. "These are the part of the penis that repond most readily to stimulation. That's why evolution gave you tits."
She grinned. "I thought evolution gave us breasts to feed our children."
"That's right, evolution did give you breasts to feed your children, but it gave you tits to help make them."
~.~.~
She rubbed her fingers over the head of his cock, eliciting a long sigh. Her fingers still moving lightly, she looked up at him. "So this is the part of the penis that most responds to stimulus?"
"No," he said. He used two fingers to point emphatically to his eyes. "These are the part of the penis that repond most readily to stimulation. That's why evolution gave you tits."
She grinned. "I thought evolution gave us breasts to feed our children."
"That's right, evolution did give you breasts to feed your children, but it gave you tits to help make them."