A very satisfying conclusion

This clearly caught them by surprise. I smiled as I watched them size each other up. Christine would be wearing Ava’s camisole, which was probably too large for her, as well as her leggings. And Ava would cover her tits with Christine’s too-small t-shirt and reveal her legs in her pleated skirt. I was looking forward to getting to see each girl’s other set of assets, and they had **** but to comply.

“Yes, sir,” Christine said.

“Whatever you say, sir,” Ava replied. This little display of submission really got to me, and I started to wonder where it might lead.

Christine got out of her seat, and Ava crawled past me. They both slid into the lavatory, leaving me on my own. My hard-on calmed and I took several deep breaths. After a few minutes, I was delighted to see the girls return.

Ava’s long, pale legs were creamy and smooth under Christine’s skirt, which was even shorter on her than on her half-Asian friend. The skirt barely covered her ass, which I hungrily stared at as she approached our seats. Her chest, too, was almost hilariously on display as her giant boobs strained against the shirt was one or two sizes too small. I gaped at her legs as she crawled in front of me, not quite glimpsing her pussy but knowing it was very, very close to the air.

As Christine sat next to me, I got a nice look at her, too. The camisole was, indeed, too large for her, and her B-size tits were easy to see when looking down a blouse built for D-cups. It’s not that her nipples were just flailing about, but they were easily on display when she turned at just the right angle.

“Like what you see?” Christine asked.

“Yes,” I said, “Yes I do. You are both very sexy.”

“Thanks, Teach,” Ava said.

“I’m impressed you were able to maneuver in that bathroom.”

“It’s pretty tight,” Christine said. “But big enough for two.”

The pilot came over the speaker, announcing that we’d start our descent in about fifteen minutes. I knew that the time had come—now or never.

“Okay, girls, I’ve got one last double-dare for you.”

“What's your assignment, Mr. Clark?” Christine asked playfully.

“Here’s the deal,” I said. “I really liked Ava’s o-face again, so I’m going to give it to her again.” The girls looked a little shocked and a little thrilled. “And then Chris is going to blow me in the bathroom.”

The girls locked surprised eyes with one another, but I plowed ahead, not waiting for them to respond. I used both hands to gently pull Ava’s knees apart, and she offered no resistance at all. I licked my fingers and placed them between her legs, lifting up her skirt to see her pussy. She had dark fuzz over her lips, not a wild bush but not totally smooth either. As my fingers slid between her slit, I could tell that she was absolutely sopping wet. I leaned over to her neck, licked under her ear, and whispered, “Let Teacher show you how it’s done.”

She softly whispered back, “Yes, sir.”

I rubbed her clit with one hand, pinching her nipples with the other. Occasionally, I dove deep into her pussy with one finger, two fingers, once even three fingers, giving attention to her clit from one side, both sides, the other side, directly on top… She was writhing, pinching her own nipples when I wasn’t, and biting her lower lip to keep from moaning out loud. I was very confident I could make her cum, but even I was surprised at how quickly she orgasmed. She clamped her legs together, trapping my hand between her thighs and squeezed her eyes shut. She bit hard on her lip, grabbing my arm with her free hand as she writhed about in her seat.

After several seconds, she released her grip on my hands, allowing her breathing to come more steadily, and she opened her eyes. She looked first at me and then at Christine, and she immediately started laughing.

“Bitch!” she said, and as I turned, I saw that Christine was putting away her phone. Clearly she had been filming the whole thing.

“What?” Christine asked, feigning innocence. “Mr. Clark said he wanted an o-face, and I was just trying to help.” I secretly wondered how many times Christine was going to get herself off to that footage. But for now, we had a different job.

“Okay, daredevil,” I said to Christine. “Come with me.” Ava waved a happy farewell as I led Christine by the hand into the small lavatory. I closed the toilet seat and sat her down on it. I pulled down my shorts and lifted one leg out so I could straddle her legs with my own. In this position, I could easily see her loosely-clad tits, and my cock was perfectly positioned in front of her face. “Now you pay me back for that A I earned you.”

“Yes, sir,” Christine said again and opened her mouth right up. I grabbed the back of her head and guided her to my rock-hard cock. She held my balls in one hand, the base of my shaft in the other, and dipped her head back and forth, causing the most delightful wet sensation on the tip of my cock. She started slow at first and sped up, squeezing my balls at just the right moments to distract me from unloading deep into her throat. Almost as if she could sense my feelings, Christine would pull back, take me out of her mouth, and lick my shaft right when I was about to cum, giving me a few seconds to calm down before diving back in. My hand gripped her hair and I knew I was getting close.

Not wanting to be teased anymore, I held her head firmly. I thrust into her mouth, her hands stroking my shaft and gurgles of saliva spilling down her face. The pressure built, I pushed deep into her mouth, and the most glorious rush of cum came spurting out of my cock. I held her steady, pumping load after load into her little mouth and watching it dribble down her chin and onto her small exposed tits.

I gave a few more thrusts into her mouth as the sensation of the most magnificent blowjob of my life subsided, and finally I released her from my cock. She smiled at me, cum all over her chin and face. She licked her lips and swallowed what was in her mouth, scooping the rest from her face with her hands and reaching into her shirt to rub my seed over her tits. Holy shit was she dirty!

We pulled ourselves together and made our way wordlessly back to our seats. Ava was idly playing with her own pussy as we sat back down. “Did you have fun?” she asked. We both just grinned.

The seatbelt sign came on, and our funny business had to come to an end. We kept talking of course, and though we were a bit less horny, I still pried enough to find out about a few of their more salacious stories and unfulfilled desires.

When we parted ways in the airport, my mind was reeling with the events of the flight of a lifetime. As I pulled my rollerboard to the rental cars, I got a text message. It was a reply to a group-text Christine had cued up on the plane when she took my phone. Apparently, she had texted “Hello from mr clark” to both girls, and now Christine had replied with a picture of her pussy. The message read “One of us still didn’t cum.” And then a reply from the other number: “Jillian’s gonna love you.” A moment later, an address popped onto the screen.

And that’s the beginning of the story of the best AP test grading session of my life.