Deep in her rectum

You continue pumping in and out of her ass trying to hold in your cum until you can feel yourself right on the verge of orgasm. At this point you bury your cock as deep as you can in Mia's rear, mashing her pussy down into Tracy's face. As you do so, you finally release your cum deep into her ass.

"Oh fuck, I can feel you filling my ass with your cum daddy."

Even you let out a slight groan as you empty your 4th load of the evening into Mia's ass. You pull your cock out and spread her ass cheeks, giving her asshole a lovely little gape. Your cum is nowhere to be found, clearly buried deep in there.

"Push my cum out of your asshole whore, so your sister can get a treat."

"Yes daddy." Mia seems much more happy playing along now, it seems you've really broken her in. Her lust has gotten the better of her and she's now your obedient little whore.

Tracy pulls her tongue out of Mia's pussy and opens her mouth wide, ready to receive your cum from her sister's ass. Mia focuses hard as she struggles to push your cum out of her rectum, the muscles in her ass are visibly contracting and relaxing as she makes repeated attempts to push it all the way out. After a few attempts, she finally manages to do it and your warm and thick sperm comes bubbling out of her ass. It pours down past her pussy and drips into Tracy's mouth, filling it up with your surprisingly large load of cum. Tracy plays with it in her mouth a while, which gives you an idea.

"Don't swallow slut, I think your sister's more than earned that load of cum. Both of you get down on your knees."

Tracy has a disappointed look on her face but gets down onto her knees alongside Mia, still holding your cum in her mouth. The two of them look at you expectingly, awaiting instruction.

"Give your sister her reward slut, and make it sexy."

Tracy is hesitant to part with the salty semen in her mouth but still does as she's told and turns to her sister. The two of them pause and look at each other for a moment, unsure of what to do next. It's funny how there's still some awkwardness between them even though they've been eating each other's pussies for the last hour. Mia eventually takes the lead and gives a cheeky smile to Tracy before sticking her tongue out and opening her mouth wide. Tracy is quick to follow on and raises herself up before leaning over so she's looking down into an identical set of eyes to her own. Mia is softly panting as she looks up at Tracy, awaiting her reward. Finally, Tracy parts with the cum in her mouth, slowly dripping it all out into Mia's mouth. Some of it slightly misses and drips out onto Mia's chin before falling down onto her tits. For the most part, it fills Mia's mouth and once Tracy's finished spitting it all out, Mia gulps down your load before smiling up at her sister, taunting her.

"You dropped a bit slut."

"Sorry sir."

Tracy lowers down and starts licking up the cum on her sister's tits, spending some extra time sucking on her nipple, to make sure she gets it all. She then goes back into position and spits it out, getting it all in Mia's mouth this time.

"Well done girls. Mia, why don't you give your sister a kiss to say thanks."

Mia looks at you a moment but then accepts the task she's been given and hesitantly leans into her sister before locking lips. The two of them passionately make out, spit dripping out of their salivating mouths and spilling down onto their tits.

You watch on as the twins sensually make out with each other, taking some much needed time to recuperate. The two of them seem to have really gotten into it now, playing with each other's bodies as they stick their tongues down each other's throat.

After some time you can feel yourself recovering and your cock starting to get hard once again from this display. You stand up in front of them before asking "You girls ready for round 2?"

The two of them pull off each others' face and turn to you giggling before synchronously saying "Yes sir."