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"...and at the end a slight swerve to the right. No, not so rough, the movement has to be much smoother. Goodness, Potter, it really isn't that hard, is it?" said Severus in frustration.
"It's okay. I think I've got the movement figured out now." replied Harry annoyed.
"Well then, use the spell on yourself now." said Severus with a smug expression on his face.
Harry grimaced but stifled any further retorts and pointed the wand at the centre of his own body. "Humido Latius!" he said, making sure to execute the movement as fluidly as possible. His mouth formed into a surprised O as he felt the unfamiliar sensation in that particular spot.
"Umm... how do I know if the spell worked properly?" the Gryffindor asked uncertainly.
Severus sighed deeply. "You must be able to tell if it feels the same as when someone else cast it on you?"
Harry almost choked, "And how would I know if it's never happened before?"
"The feeling should not be much different from just manual preparation without the spell." Severus clarified.
The Gryffindor gave him a dark look. "Do I have to spell it out for you to understand? I have no idea about such things because I've been really busy elsewhere for the last few years. So no, I don't have any practical experience so I don't know what it should feel like."
Harry thought he saw a strange gleam in Severus' eyes, but it was gone as quickly as it had come.
"Can't I just cast the spell on you and you tell me if it worked?" the Gryffindor asked hopefully.
Severus snorted. "You don't seriously think I'd be a bottom, do you? Unlike you, I'm more of a top."
"How would you know that when even I don't?" defended Harry vigorously.
With two steps, Severus stood directly in front of the Gryffindor and lifted the latter's chin so that he had to look up into his jet-black eyes from a few inches away.
"You underestimate how much of yourself you give away. I can see it clearly in your gaze, how much you would enjoy lying under another man who dominates you and gives you what you need. How much you want someone where you can let go yourself while he only takes care of you and your needs." purred Severus, looking into widened green eyes.
The Gryffindor's breathing quickened and Severus released him, taking another step back.
"You could test it with your fingers to see if the spell worked like it was supposed to." the Slytherin said again in his teacher voice.
Harry blushed, but started to unzip his trousers with a sheepish look.
Severus' mouth dropped open and it struggled inside him as he clarified "I didn't actually mean here and now."
The Gryffindor's face coloured even darker. "Sorry." he muttered bashfully.
"You know what, on the other hand, it might make sense for you to make sure you can cast the spell properly right now, so you might as well get on with it." Severus said, and it was only helped by his years of work as a spy that there was no trace of his excitement in his voice.
Harry let his hand slide down the back of his open trousers.
"Take one finger first." Severus instructed him. "Try to insert it as far as you can."
The Gryffindor made a noise that sounded suspiciously like a moan and it took Severus some restraint not to let his hand wander into his trousers as well, though rather to a certain other hard spot that was persistently drawing attention to itself.
"Is it working without much resistance?" asked Severus with an extra professional voice.
"Yes, sir." replied Harry in a tone that only aroused the Slytherin more.
"Then add a second finger now," Severus demanded. "Although maybe you should pull your pants down a bit first. Then you can get at it better and I can make sure you're doing it right."
Harry turned his back to him and let his trousers fall down. His fingers disappeared between his buttocks again and when the Gryffindor leaned forward a little and spread his legs further apart, Severus had a perfect view.
He suppressed a groan with difficulty as he watched two of Harry's fingers disappear into the seductive body again and again. It was obvious that Harry had apparently performed the spell perfectly, but nothing could have been less interesting for the Slytherin right now. He finally allowed himself to put his hand over the bulge in his groin and slowly rubbed his palm over his fabric-covered erection.
Severus swallowed and his voice was audibly harsher now as he motioned for the Gryffindor to feel for his prostate. He realised the angle was difficult, but all the better for it, as it turned out shortly afterwards.
"I don't think I can find it. Could you help me with it?" asked Harry with a tantalising smile as he glanced over his shoulder at the potions master.
Severus stepped so close behind the Gryffindor that their legs touched and Harry's hand brushed against the Slytherin's groin because of the groping motions.
He enjoyed the sight up close for a moment, then Severus reached out and gently ran a finger down the Gryffindor's back, down the cleft to Harry's fingers. Severus carefully slid the finger between Harry's ass cheeks and also entered the hole, which was well dilated and moist by the spell.
It didn't take him long to feel the prostate and he gently ran his fingertip over it, causing the Gryffindor to moan and shiver.
"More, please..." pleaded Harry and the Slytherin was only too happy to comply with his request. As Harry withdrew his hand, Severus sank more fingers into the Gryffindor until there were 3 digits inside. He watched with a fiery gaze as they disappeared into the hot body again and again.
"Is this what sex feels like?" the Gryffindor asked with a moan and the Potions Master almost came at the seemingly innocent question while he was doing things so not at all innocent to the younger man.
"Would you like to find out?" asked Severus in a dangerously dark voice. He wouldn't be able to control himself much longer anyway. He would only need the slightest sign from the Gryffindor and he would finally give in to his desire and release his impatient hardness from his trousers and finally sink into that gorgeous body.
"Oh yes, please... please!" begged Harry at that moment and the Potions Master could have cheered at that welcome response.
He finally freed his throbbing erection from his trousers and stroked it teasingly across the bottom in front of him. Mind you, the Gryffindor wasn't here just for fun, he was supposed to be learning something, so it was a good opportunity to teach him another spell.
"Listen carefully, there's more than just the Humido Latius spell to prepare your sex partner." he murmured in Harry's ear, who shuddered in response. "There's also the Humido Phallo to prepare yourself. That one feels like this..." With a wave of his wand, he spoke the words "Humido Phallo" clearly and the younger man yelped as he felt his hitherto neglected member being encased in a warm lubricant. With another flick, Severus applied the spell to himself as well, now rubbing the tip of his damp penis against Harry's anus.
"Are you sure this is what you want?" asked Severus again, just to be on the safe side. It would be an extreme shame to have to break off at this point, but he wouldn't want to be the one to steal the hero of the wizarding world's first time without his consent. And he still had enough self-control that he would be able to stop. Even if it would take some doing.
"I'm sure, damn it! Now get on with it and don't keep me waiting any longer!" the younger man demanded vehemently to mask his nervousness.
"Well then..." said Severus and leaned his body forward so that the glans finally penetrated the hole. The lube made it easy to penetrate the willing body beneath him without resistance and he had to force himself to slow down and not sink into him in one go. He stroked the Gryffindor's back gently as his cock disappeared completely into the beautiful body and he marvelled at the sight of them connected.
"Are you all right?" inquired Severus.
"Unused to it, but I think I like it. It doesn't hurt either." replied Harry with relief.
"That's exactly what good preparation is all about. Sex is supposed to be fun, not painful." the Slytherin couldn't help but explain.
"Shouldn't you start moving then?" asked Harry teasingly and Severus could just hear the younger man's grin.
He pulled back a few inches and then thrust into the Gryffindor's body again.
After doing this slowly a few times, Harry met his thrusts impatiently. "Come on, you can go faster. I'm not made of glass." he urged.
"I thought I should maybe be a little more careful since this is your first time." Severus said, having been extra carefully so as not to overwhelm the younger man.
Harry snorted. "So what? I'm still not a princess. I won a war, for fuck's sake. So I can assure you that I can definitely take more."
Severus grabbed the Gryffindor by the hips and said darkly, "As you wish..." before he began to sink himself into Harry again and again with powerful thrusts.
"Fuck! This is exactly how I imagined it!" moaned Harry enthusiastically and Severus was all too willing to help the younger boy make his dream come true.
He noticed that Harry's hands had moved to his groin by now and that he was taking care of his cock, which had been criminally neglected so far. In Severus' opinion, however, it was his privilege and until now he had not had the pleasure of caressing this particularly tempting part of the Gryffindor. So with one hand he shooed Harry's hands away and instead placed his own around the throbbing length.
The warm cock felt good in his hand and Severus decided that this part of Harry was just perfect too. Why did this damned hero have to be perfect at everything? If he were anyone else, he might have been able to secretly increase his chances with potions or spells, but what a chance would he have with the famous Harry Potter? On the other hand, he was here with Harry now and if the Gryffindor wasn't lying, he was the first to see and experience him in this way. So perhaps he was allowed to hope for more after all? Maybe he shouldn't worry so much and just enjoy the moment when he had Harry in his hands like this. In the truest sense of the word.
He let his hand slide up and down Harry's cock with varying pressure in rhythm with his thrusts and enjoyed the sounds he could elicit from the Gryffindor with it. He could hear perfectly well that Harry was not far from his orgasm and so he too drove himself faster and deeper into the Gryffindor until he came moaning heavily. The muscle contractions inside Harry also helped Severus to his own climax shortly afterwards.
Breathing heavily, they stood there and when the Slytherin realised that Harry was barely able to stay on his feet, he took him in his arms and dragged him with him to his teacher's chair, where he sat down and pulled Harry onto his lap.
Harry snuggled up to him and sighed contentedly as Severus stroked a hand through his hair.
"Well, I've had to teach the Sex Education lesson many times, but it's never been this intense." Severus said as the silence grew too long and he feared the Gryffindor would soon fall asleep on him.
Harry sat up and looked him in the eye, frowning. "I certainly hope it's not a habit of yours that you use class to have sex with students."
"Don't worry, you're the first student I've ever did anything like this with and it's definitely not because you're my student." Severus assured him. Then he couldn't help but say challengingly, "Could it be that you are jealous?"
Harry bit his lip and turned his head away. "Maybe... I have to admit being kind of bothered by that thought."
Severus was a little unsure if he should take the risk of opening up too much, but then again, what did he have to lose? He placed a hand on the back of Harry's neck and gently pulled him closer until the Gryffindor looked at him with wide eyes and allowed their lips to meet. The first kiss was shy. Almost too gentle for what they had been doing for the past hour, but the Gryffindor quickly became bolder and opened his mouth to Severus' tongue.
After they had kissed a few times, Severus broke away and said carefully, "If it makes you feel any better, I'm happy to tell you that there's no one else in my life at the moment."
Harry looked at him with an adorable smile.
"Very well. Then what do you say, could we perhaps continue the lessons on this subject outside of class? In private?" the Gryffindor asked hopefully.
"I think that's the best idea you've ever had, Harry."
END