Geeks are so cute when they're freshly laid, thought Brittany, listening to Albert explain the laws of gravitation yet again. She was having trouble following the drawings he made on her nude torso, since he was sketching them with his fingers alone. If he isn't careful with his diagrams, Brittany thought again, I'm going to jump him again. Albert was talking as he drew.
"So the force of attraction between two bodies is directly proportional to the square of the distance between them," he was saying.
"So, is that like 'out of sight, out of mind' when they're far apart?"
"Well, yes, I suppose so." He looked puzzled. "I'm speaking of things like planets, though. I'd be attracted to your body if it was hidden on another continent."
"What else can you teach me about physics?" She snuggled up against him, thereby increasing the forces of attraction between their bodies.
"Well, there's the laws of momentum and inertia. Body's at rest tend to stay at rest..."
"That's no fun!"
"...but bodies in motion tend to stay in motion," he said, stealthily (for a geek) inserting his re-aroused manhood where a push would stimulate an equal and opposite reaction. He began to apply such pushes in sinusoidal waves, achieving the aforementioned reactions. He was debating whether to explain elastic and inelastic collisions, using their flesh to illustrate when she rolled him onto his back.
From the initial velocity he imparted, Brittany decided to show him what she'd learned about acceleration and the force of gravity, lifting herself to drop on his, um, fulcrum. She knew how to take mechanical advantage, and anyway, it was her turn on top.
"Oh God!" Albert shouted, "Don't make me come in her pussy again!"
"Albert," rasped Brittany, "stop telling God what to do."