Change of pace, they both want more.

Mr John couldn't hold out for much longer, and he had bigger plans for these two young sluts. He pulled his cock out of Joe's mouth, much to her dissapointment. Both girls looked up at John with a sulken expression, but both turned to smiles when he said, "Get up and bend over the desk you two." Both Sarah and Joe stood up and removed the rest of their clothes, then bent over Mr John's desk, giving him a great view of their moist pussy's and tight anus. Mr John stroked his cock as he took in the view before him.
"Fuck my pussy, please!" Sarah pleaded as she turned her head around and pouted at Mr John.
"No! Take my pussy!" Joe screamed.
The two took turns, begging for Mr John to take their moist pussy's. Mr John stood their stroking his hard cock not sure which one he wanted to take first. As the two girls continued their begging for Mr John, Joe suddenly said, "My ass, take my ass now! Forget my pussy, fuck me in the ass now!"
That was all Mr John needed to tip the scale in Joe's favour. He stepped up behind her and guided the tip of his cock at her backdoor. He pressed forward firmly and the head popped in. Joe let out a gasp as Mr John's cockhead slipped into her anus, it was a tight fit, especially as he was taking her ass raw. Mr John spat down on his cock for lubrication and then pushed forward again. Joe's ass began to relax and widen and another inch pushed it's way in. Slowley, inch by inch Joe's ass took Mr John's seven inch's into her ass. John waited a moment for her ass to realx further, and then started a slow pumping action. Sarah who was busy fingering herself as she watched Mr John's cock slide in and out of Joe's ass grabbed her by the hair and kissed her madly. The two girls tounge's were darting in and out of each others mouths as Mr John continued to fuck Joe's tight ass.
"Mr John," Sarah begged, "I want it too..."
Mr John pulled his cock out of Joe's ass and placed it at Sarah's swollen pussy lips. With one long hard thrust, he sank his cock deep into her cunt. "Ah yeah, fuck me!" Sarah yelled. Mr John slammed he cock into her pussy for only a few strokes before puling out again. "Hey, what are you doing?" Sarah asked. Mr John moved over and plunged his cock back into Joe's ass. "Ahh!" Joe screamed as his cock again invaded her ass. But just like he did to Sarah, after a few strokes he pulled out and fucked Sarah in the pussy again. This went on for a while, he took turns fucking each girl for a few strokes, swapping between the two. Both girls were going crazy, each begging more to be fucked for longer and harder, but Mr John refused to play it their way.
All of this ass and pussy fucking, and the double blowjob from before was making it very hard for Mr John to not blow his load right away. With each stroke her knew he was getting closer to a massive orgasm. Finally after about a half an hour of swapping between the two girls, he shouted, "Ah fuck girls, I'm going to come! Get down on your fucking knees, I wanna shoot all over your faces!"
Sarah and Joe were quick to respond, and were on their knees, mouths open, waiting. Mr John stroked his cock faster and faster, feeling his cum build in his balls. "Come all over my face, I want to taste it!" Joe said as she reached out and rubbed Mr John's balls with her hand. "In my mouth, shoot it in my mouth!" Sarah said, licking her lips. That was it, Mr John let out a scream and blasted the two sluts with all his cum. They took it in their mouths, eyes, hair, cheeks, by the time Mr John had finished they were both covered in his semen. The two gilrs licked each other clean and sucked that last few drops out of Mr John's cock.

Later when they were all getting dressed, Mr John said, "Girls, some friends of mine are having a party tomorrow night, would you both like to come?" The two girls quickly said yes and Mr John gave them a card with the address.