I started putting my clothes back on when Elizabeth stopped me.
"You're going to have to go nude," she instructed, smiling devilishly. Since she was still "using" me she was well within her right to force me to go naked. So I simply chuckled and left my clothes in a pile by the door.
"Wait a second," Rebecca called out, "I want to fuck John too."
"Then come with us to breakfast and fuck him there," Elizabeth replied.
"I'm going to eat later. I'm using both of you now, and then after you can eat at the dining hall," Rebecca explained.
Elizabeth and I simply nodded. Any person could use any number of other people as long as it was reasonable. Since she was preventing us from going to breakfast for sexual reasons, it was completely legit.
"Ok, what do you want us to do?" I asked, stroking my already erect dick. Like any other guy, it only took about ten seconds to get rock hard again after cumming.
"Hmm, how about a daisy chain? I suck your cock, you'll eat Elizabeth out, and Elizabeth eats me out. Then I'll have you do me doggy-style while Elizabeth makes out with me," Rebecca said.
Rebecca was usually a more reserved and quiet girl, but occasionally she would fuck me when Elizabeth would bring me over. But normally, Elizabeth would just masturbate and watch when Rebecca and I would fuck. I guess variety is the spice of life.
We got onto the ground and went at it. Having eaten her out many times before, I vigorously attacked Elizabeth's pussy just like I knew she liked it, causing her to shudder and squirt a bit into my mouth. Meanwhile Rebecca, like all teenagers, was an expert cocksucker, and was making it hard for me to not cum.
Elizabeth squealed, and then came. Almost like a reaction, I came too, and I heard Rebecca swallowing my semen in several large gulps. We laid on the ground for a moment, enjoying the afterglow. Elizabeth's vagina was still leaking, dripping onto my face as it pooled on the floor.
I stood up, my cock already getting hard, and positioned myself behind Rebecca. She got off the floor and onto her knees, all ready to receive me. I slowly inserted my dick into her sticky vagina, and began thrusting. Meanwhile, Elizabeth got to work kissing and fondling Rebecca all over. She passionately kissed her roommate, reaching down to her breasts every few seconds to give them a squeeze.
I noticed that some of my ejaculate had gotten onto Rebecca's shirt and hair. But of course this was no big deal at all. People had so much sex that owning clothing that wasn't cum-stained was impossible. In fact, manufacturers sometimes added fake cum stains as part of the design, or designed the clothes to be particularly discolored in the presence of sexual fluids. By the looks of it, her otherwise transparent shirt had several opaque blotches from where semen had hit it.
Eventually it was getting too much for me, so I came, shooting more of my cum into her pussy. I pulled out, sitting and watching the two roommates still making out, until Rebecca pulled back, realizing I had finished.
I looked up at Elizabeth, noticing my cum (which she got from kissing Rebecca) dripping from her mouth.
"Are you sure you don't want to come with us to breakfast?" I asked Rebecca.
She climbed back onto her bed, my white fluids dripping from her pussy onto the navy sheets, now stained with even more white blotches. "That's ok, I just wanted a quick fuck," she answered, and continued using her phone and stroking herself.