I noticed several things simultaneously, but two things stood out. The first was that we were no longer alone - Cathy's best friend Rebecca, whom I'd also taught for several years, was here as well. Becky had gone down to the same university as Cathy to study, although she was in a different course and lived in a different place. The other thing I noticed was that both the girls were standing just outside the bathroom door in their underwear.
Cathy was wearing a black half-cup bra, which seemed to boost her A-cup breasts up and together, and a matching black pair of panties, tightly hugging her tiny waist and slight hips. Becky is smaller than Cathy but with a much fuller body, long blonde hair and a fairer complexion. Her underwear was white, although with a similar design to her friends'; a half-cup bra presenting her C-cups, and a matching pair of panties with a little lace on the sides.
I realised that I was staring, that I hadn't said anything for several seconds, that my mouth was wide open and that I was totally aroused by the amazing sight before me.
"Please do this for us, sir," Becky said softly, stepping slowly towards me. "We both want to learn how to please a man, and we both want to pay you back for being the best teacher we ever had. We thought that this would be an ideal way for you to teach us something else, while enabling us to thank you at the same time."
By the time she'd finished speaking, she had reached the place where I was standing, still rooted to the spot. She pressed her body into mine on my left side, and started kissing the left side of my face as she finished speaking, rubbing her body up against my side.
Cathy quickly followed her and began mirroring her actions on my right side. The two moved closer and put their hands on the bottom of my shirt; Becky began unbuttoning it and, once she was finished, Cathy pulled it back. They both then began kissing my chest, and rubbing my considerable stomach.
I still hadn't moved, and couldn't believe what was going on. Any inclination I might once have had of stopping this had now completely deserted me. I slowly realised that I was not only going to have sex with my favourite student, I was going to have sex with my two favourite students, both at the same time. Upon arriving at this decision, I was finally unfrozen. I shrugged out of my shirt and put an arm around each of the girls, then kissed the tops of their foreheads.
"Does this mean that you'll do it?" Cathy asked, looking up at me with her hopeful puppy dog eyes.
In reply, I took her in my right arm and kissed her full on the lips. After a few moments, as she allowed the shock to dissipate, she allowed her lips to open and permitted my tongue access deep into her oral cavity. Despite her concerns, I found that she wasn't a bad kisser at all. I became aware that my other arm was now free, so I began running it up and down her back, from her bra strap down to her panties and then back up.
Meanwhile, I felt my belt being loosened, as Becky began to undo my trousers. Still kissing Cathy, I slipped my shoes off as Becky slid my pants down to the ground. As I stepped out of each leg, she unrolled the sock from each foot and placed the sock inside its respective shoe, which she then placed neatly next to the window.
I let Cathy go and took Becky in my arms, lifting her from the floor and then kissing her as I had kissed her best friend. I was immediately aware that Becky had a lot more experience in this than Cathy had; she was a much more confident and assertive kisser.
"When did the two of you decide to do this?" I asked them, when I finally paused for breath.
"Cathy has wanted to do this for years," Becky replied. "We used to joke about what would happen if one of us got with you, and how the other would take it. We talked about it a lot at New Years, and then some more when we went down to university, and then finally decided that there was nothing stopping us now that we were out of school and no longer your students."
"But both of you together, like this? Doesn't that make things a little uncomfortable for you, or awkward?"
"Oh no," Cathy replied, "We've both seen each other naked plenty of times. We've had lots of sleepovers during the past few years."
The two girls giggled when she said the word sleepovers, leading to my next question: "Are you saying what I think you're saying?"
They didn't reply verbally; instead, Becky turned to Cathy and the two reached for each other, folded the other into their arms, and then began kissing. Their mouths open, every so often I could see the flick of a tongue from one mouth into the other. Their hands wandered all over each other's bodies, working their way up from the small of their backs, across the shoulders, down the sides and back to the centre of their bra straps. Almost simultaneously the two girls unclasped their friend's bra. They stopped kissing and turned to face me. As one, they shrugged their bras off over their shoulders and onto the floor.
I couldn't think of anything at all to say. I just keep looking from one girl to the next, and then back again. I'd had no idea just how hot these two girls were! Rebecca was a blonde bombshell but she'd always seemed to dress down in the ugly terracotta uniform we'd made them wear at school, and Catherine had always seemed too slim and angular to be a sex goddess. But now... I quietly revised my theory about Rebecca's breasts; now I could actually see them, I realised that they must in fact be a full D cup. They were so round and full, almost too big for the tiny body they blessed. Cathy's were much smaller, her nipples tiny buttons atop two slight rises, but they were perfectly proportioned and well rounded.
After realising that I was still too stunned in a state of shock to do anything, the girls walked over to me and, taking an arm each, led me to the bed. They sat me on the edge and then pushed me back, so that I fell back onto the pillows at the head.
The next thing I was actually conscious of was my underwear being tugged at. I looked down and saw the two girls kneeling on the floor, one either side of me, caressing my upper thighs with their small, delicate hands, the cool, silky smooth feel of their skin doing nothing to alleviate the heat of my loins. As I watched, the girls took a side each of my briefs and slowly pulled them down, keeping their eyes firmly on the erected tent in the middle. It didn't take too long for the centre pole to be freed, and at that moment I knew that Cathy was definitely a virgin - her eyes were wide open in shock, as if she had never before seen what she was now seeing. Becky seemed less impressed. I am only average sized in that department so I guessed that she may have experienced, or at least seen, a more endowed man than myself. But I have nothing to be ashamed of and as everyone knows it's not the size of the tool but how you use it that is important.
With my underwear on the floor I was now completely naked, my groin being worshipped by two nearly naked teenaged girls. Becky began planting little kisses all over my dick, giving the head a quick flick with her tongue when she kissed the tip. She then urged Cathy to do the same, and I groaned as Cathy followed her friend's instructions and took the tip of my penis into her mouth. She opened her mouth wider and sank lower down on me, and then I could feel her inexperienced tongue gliding along the underside of my shaft.
Becky was still whispering in Cathy's ear, and Cathy now released me and got to her feet. Becky's mouth quickly replaced her friend's, and while Cathy had been good, Becky's obvious experience was immediately apparent. Cathy watched her friend for a moment, and then made sure that she'd caught my eye before cupping her own breasts in her hands. Cathy's hands moved down and forward to allow the forefinger and thumb on each hand to grasp at one firm, erect nipple each. Her tongue darted out and ran across her lips as she continued to tweak her nipples, rolling them like she was rolling a cigarette or something. She released her hold on herself and then ran her the palms of her hands slowly down the sides of her breasts and further, down her hips until they stopped at her outer thighs. Her fingers hooked under the sides of her panties and then slowly drew them down. She leaned forward as she pushed the underwear down her legs, giving her small breasts the benefit of gravity to help form a delectable cleavage. Cathy daintily stepped out of her panties and looked up at me, still hunched forward, and brought her upper arms closer together to push her cleavage out further, making it deeper. Her hands came back up and once more took a grip of her nipples, before she let go and stood upright again.
Completely naked now, Cathy climbed up onto the bed and crawled up alongside me, then bent down to kiss me full on the lips. Her tongue invaded my mouth and began to wage a war of conquest against mine, which I was glad to struggle against but also to ultimately lose. She broke the contact and raised herself back, manoeuvring a breast into my mouth as she did so. My mouth immediately captured it and my tongue began battering the nipple into submission, as Cathy gasped in shock and then quickly pulled away. She sat up on her haunches next to me, then looked back at Becky.
The blonde was kissing and licking all around my groin area, but now she stopped and looked back at her friend. She nodded once, and then returned to the job at hand. (Or was it the job at mouth?) Cathy moved closer to me, sat upright, lifted her right leg and presented me with the most gorgeous shaven snatch I had ever seen in my life. It hovered above my face for a second or two as her right knee touched base on the other side of my head, then she lowered herself down onto my face and my tongue immediately went back into action.
I gave her everything I had, licking away like a cat at a saucer of cream. My hands ran up her smooth thighs, then around to her buttocks, kneading and clenching the tight, firm, smooth flesh there. I could feel Becky gently massaging my dick with one hand, and kissing the skin around the general area, but it felt so far way - my main focus was now on giving Cathy the best eating out of her life.