Ask if you can take a break (Yeah, right...)

You say, through tired breath "Hey, you guys mind if I take a minute? You really roughed me up just now..."

Ava and Mia look at each other confused. Suddenly, Ava gets a devious smile on her face and quickly moves over to Mia, whispering something in her ear. They nod to each other and stare back at you, making you nervous.

Ava speaks up "Sure thing, buddy. Make yourself comfortable on the couch..."

You still feel a bit nervous, but move over to the couch and take a seat. Unexpectedly, Mia walks over and takes a seat next to you, moving in really close.

She leans in a bit closer and says, softly "Hey, why don't you take a seat on my lap? I can give you a little massage to loosen you up a bit."

You take a look at Mia and see that she's still fully erect and her cock is glistening with spit after having her way with your throat, but you think "Why not?" and oblige. You move over to Mia, and sit on her lap, facing away from her. You can feel her hot dick resting on your back, but she doesn't seem to be making any advances yet. You see Ava a few feet away, just sort of looking around as if waiting for something. Mia starts rubbing your shoulders with her soft hands.

The massage feels relaxing, as she moves her hands down your back, rubbing it with care. She moves her hands down to your hips, not stopping the seemingly innocent massage. But then, you feel her hands tighten around your hips, and her cock spring up, as if getting ready for penetration. Before you can react, she lifts your lower half up in the air, and drops you down on her dick, making her cock dig straight in your ass. You yelp in shock by the unexpected feeling of having your anus filled up with Mia's girl dick. She keeps holding on to your hips and lifts them up a few inches so that she has some room to thrust into your butt. Soon enough, she starts pummeling your ass with her cock with short and fast thrusts.

You see Ava walking toward you, laughing and saying: "Oh my god, I can't believe you fell for that! You should know, that there's no rest when you're dealing with us. Now, open up that mouth of yours and let Ava in..."

You stare up at Ava and do as you're told. You open wide and let Ava's throbbing cock slide in your mouth and down your throat, as she moves in closer and closer.

When you've taken her to the base, she says "You know what, I'm tired. Suck me off yourself."

You take the opportunity and move back from her cock, giving you room to breathe. You start sucking Ava's dick, coating it in spit and tasting the aromatic precum that leaves its tip. All the while, trying not to get too distracted from the pounding that Mia is delivering from down below. After a while of sucking Ava's dick, she seems to get a bit annoyed that you're not taking it all the way down your throat.

She speaks up "OK if you don't know how to use that throat of yours, I'll have to show you. Wanna help me out with this one, Mia?"

Mia says "Sure thing, sis!"

She then moves one of her hands from your hip to the back of your head, pushing your head down on her sister's cock, gagging you in result. Mia's hand starts moving back and forth, making you gargle on Ava's cock, all while being fucked in the ass by Mia. Ava's dick goes pretty deep down your throat, but not quite to the base yet. Ava decides to help out with the last few inches, by taking your head in her hands and face fucking you, slapping her balls against your chin with each thrust. You gag and ****, but are powerless to do anything about it.

As their fucking speed increases, you feel them getting close to orgasm. Mia puts both of her hands back on your hips and starts making her thrusting even harder and quicker. Your cock is already rock hard from all the times Mia's dick has rubbed against your prostate, and you feel close to cumming as well. Ava starts panting and really ravaging the depths of your mouth. With a few final thrusts, all three of you yell out in ecstasy and cum at the same time. Mia sprays her seed straight up your ass, making your belly bulge a bit from all of her cum. You feel it's warmth reaching deep into your ass as it coats your rectum. Your own dick starts shooting jizz up in the air, and your body can't help, but to shake in pleasure. Ava holds your head steady in its place as you feel her balls churn up a giant load. Right then, your mouth and throat get filled with multiple streams of hot sperm. You feel it's thickness as it slides down your gullet. You try your best to swallow as many if the loads as you can, but the dick clogging your throat, makes you cough up some of Ava's cum around her dick. Some of it even leaks out of your nose.

After you've been filled to the brim with hot girl-spunk, Ava moves away, letting you catch your breath. Mia, however, decides to stay right where she is- below you with her cock down your ass. A couple of drops of her sperm escape from your anus, flowing around her dick slowly. You can't bring yourself to remove Mia's cock from your ass, as you've already gotten used to it. But sadly, all things must come to an end. Mia lifts you off of her cock and sets you down where you were sitting at the start of this. The sudden feeling of having Mia's giant rod being removed from your anus is stimulating, and makes your cock twitch, sending out a small load of sperm still in it. You lay on your side, to let the cum flow slowly out of your ass. While you lay there, you overhear Ava and Mia speaking.

Mia says: "Well, that sure was fun!"

Ava replies: "Couldn't agree more. Thanks for having my back."

Mia nods and says: "Thank YOU for thinking of the idea to trick this guy with the massage!"

The sisters talk among themselves some more until they are interrupted by Alan speaking up through the speakers. "Well... hows everybody getting along?"

Ava says "We're doing great!" with a smile, and Mia nods.

Alan says "That's great! Glad to see everybody happy. Well, you both can get back to your room, and YOU can get back to yours. More tests to be done and all that... Oh, and don't think we forgot about that bonus!"

The girls start making their way back to their room, waving goodbye to you as they do. You also get up from the couch and start moving over to your own room. Your stretched ass and full belly make it a bit harder than usual, but you're happy that everybody left happy in the end.

You got the "Duped" ending with Ava and Mia.