“Like this, Professor Ford?” said Madison as she lowered herself to the soft carpet before her friend Lacy.

“Yes, that’s right, just like that,” I said. “Oh, one last thing,” I added, then reached over from where I sat and pulled Madison’s short black skirt up over her bottom, exposing the gentle curve of her young ass, pretty panties frozen beneath the thin material of her sheer pantyhose. She gasped and peered at me with a confused look. “It’ll help with the demonstration,” I said with a reassuring tone, wondering just how stupid these girls were.

Madison and Lacy were entitled little college girls, sent to me for private tutoring, an attempt to avert the inevitable disaster predicted by their plummeting GPAs. They were eighteen years old with the intellectual prowess of twelve year olds, and today, I was teaching them physics, a subject that neither one of these two bimbos had a hope of learning.

“Today, girls, we’re going to learn about Newton’s third law. Do either of you know what that is?” I asked, with no real hope of a satisfactory response.

The pair stared at me blankly. With no surprise at all, I felt a rush of gentle heat rise up from my stomach as the girls adopted this look of mindless suggestibility. It was what gave me the idea for this sordid plan in the first place. The way they became strangely pliable and docile whenever I asked them intellectual questions. Almost as if years of Snapchat abuse had given them such low attention spans that they couldn’t hold a conversation about anything more demanding than the plot of The Walking Dead.

I sighed, allowing them to see my exasperation. They were good girls really, and if they saw that I was disappointed, they would be far more likely to do what I told them.

“Newton’s third law, girls, states that for every action, there is an equal and opposite reaction.”

They gazed at me blankly. Lacy kicked her foot out petulantly, I could tell that I was losing her.

“Madison, take off Lacy’s shoe,” I said, trying to keep my voice low and calm, giving her the order as if it was a normal part of any high school curriculum.

Madison looked at me and blinked, as though processing what I’d said. Then she turned to her friend and lifted the other girl’s foot. Lacy gazed down at her with a look of blank surprise, but she didn’t protest. Then Madison slowly eased Lacy’s expensive open toed pump off and set it to one side.

I swallowed hard as I gazed at Lacy’s exposed foot, tanned flesh covered in sheer black nylon, perfectly painted toes squirming beneath the thin material. My heart began to race, filthy, sinful thoughts raced through my mind. How far would I be able to take this? What could I make this pair do before they realized that they were playing my sordid game?

“Okay,” I breathed, barely able to control my voice. “Now, Madison, I’d like you to lift Lacy’s foot to your nose and breath deeply inwards.”

Madison blinked and furrowed her brow. “I’m not sure what…”

I stopped her with a stern wag of my finger. “All will become clear, my dear. Now get to it.”

She nodded and frowned. “Yes, Professor Ford.”

She turned to Lacy’s stockinged foot again and lifted it to her face, studying the velvety soft expanse of her sole. Lacy looked on, not saying a word, mouth parted and breathing quickly. Then Madison lowered her head and buried her nose in the space behind Lacy’s squirming toes. Squeezing her eyes shut, she breathed in quickly and deeply. Seconds later, she exhaled but didn’t lift her head immediately, moaning softly as whatever debilitating sensation she’d provoked washed over her.

“Very good Madison. Now, what did we learn?”

Madison and Lacy turned to me with the same blank look as before. Madison’s face glowed pink with a light flush that rose up from her neck, she had a distant look in her eye.

“Okay, let me help you,” I purred. “Madison, what happened when you sniffed Lacy’s foot?”

Madison blinked and thought for a second. “It… it felt… good. Inside me, I mean.”

I smiled and clapped my hands. “Very well done!” I said. “You’ve demonstrated Newton’s third law. Madison’s action of smelling Lacy’s foot caused an equal and opposite reaction of pleasure inside her body.”

The pair looked on with stupefied expressions. Then Madison’s face melted as realization struck her. “I get it!” she smiled.

Lacy, meanwhile, looked on with the same confused bewilderment as before.

“Lacy,” I waxed, “I can see you’re not following along. Perhaps another demonstration.” I turned and looked at Madison. “Madison, please lick the sole of Lacy’s foot, starting at her heel and stopping at the tip of her pretty little toes,” I purred.

Madison smiled and nodded eagerly. She turned back to Lacy and lifted her foot once more. The pair gazed at each other with a dreamy, distant expression that could only be awakening desire. Then Madison slowly, deliberately ran her tongue over the tantalizing flesh of Lacy’s sole, taking a glacial age to traverse the dainty length of the other girl’s foot. As her sensual exploration progressed, Lacy exhaled softly, eyes narrowing, mouth parting with a hungry longing that surprised even me. Her hand lifted from the sofa beside her and she gently touched her fingertips to her breasts, caressing them beneath the tight material of her blouse.

Madison pulled back, breathless, eyes locked on her friend’s flushing face. Then she dipped forward again, wrapping her soft pink lips around Lacy’s toes, sucking hard on the squirming digits, eyes closed, lost in a world of new sensations. The pair began to writhe and squirm, moaning in a harmonious chorus of mutual pleasure. Madison’s mouth moved eagerly over Lacy’s foot, licking, lapping, nibbling the soft curve of her arch, soaking her pantyhose with her hot wetness. Lacy, meanwhile, sank further into the sofa, hands roaming over her own body, touching her breasts, her thighs, her stomach, her neck, staring at Madison as she worked below her.

I looked at the pair with rapt fascination, unable to look away from the unfolding scene that I’d set in motion. A hot fireball burned between my legs, pulsating and throbbing, sending wave after wave of sensation into my body. Unable to control myself, I reached over and touched my hand to Madison’s raised bottom, gripping her toned flesh through the thin gauze of her pantyhose. She moaned and cried out, quickening her pace on Lacy’s foot, in turn causing Lacy to beg for more. “Oh, sweet, sweet physics!” I thought to myself as my actions provoked equal and opposite reactions in the bodies of these two cavorting girls.

I sat back. “Okay, that’s enough girls,” I said, breathless. The pair fell apart, Madison setting Lacy’s foot down on her lap, Lacy collapsing limply into the sofa. The girls turned to face me, faces flushed, panting softly, hungry expressions lighting up their young faces.

“I think we’ve learned that lesson well enough,” I breathed and the two girls nodded lazily. “Now, let’s go up into the bedroom and I’ll demonstrate the physics of the rigid rod.”