"I'm gonna take a shower," Jill said when she finished licking the cum from my lips and chin, which had gotten there while we were kissing after my morning blow job. I soon heard the water in the shower running and I became lost in thought.
I lie there in bed and began reflecting upon the first two weeks of our three week vacation with the folks away. I could hardly believe it. My hum-drum little sister had transformed herself into a raving sex machine whom I was fucking at will, and when we got caught by our older sister, instead of ostracizing us, she sits and masturbates while watching us. Amy had been back two more times last week, after she got off work. Both times she had stripped naked and masturbated continuously while watching Jill and I suck and fuck our brains out. She even brought a couple of her own toys with her; one of those little "pocket rocket" vibrators and a six inch dildo. But she was very reluctant to get too near either of us. I couldn't read Jill. She had gotten pretty good at talking dirty to Amy during our sessions. So much so, that I only got a word in here and there. At first, it was to get Amy more and more turned on so she wouldn't be pissed at us, but now I began to get a small feeling it was to entice Amy into joining us! The things Jill said to Amy while we fucked sounded more like an invite than a commentary. But as I said, I couldn't read her. Later that afternoon, Jill and I were out by the pool, and I decided to bring up the subject.
"You know, Mom and Dad will be home next weekend," I said.
"Yeah, I know," she answered sullenly.
"That's really going to put a restriction on the activities," I said.
"Don't remind me. In another five or six weeks, we'll both be going back to school too. I don't want to miss any of that time not being able to fuck you." Jill's language had become brazen, yet nonchalant.
"Me either," I answered. "I was thinking about that this morning and I might have come up with a possible solution."
"What is it? Tell me!" Jill said excitedly.
"You may not like it, and if you don't, that's okay," I told her.
"Jack, if it means getting to fuck you, I'll do almost anything."
I smiled at her. "Well, if we could somehow get Amy to become 'more involved' in things, maybe we could her to make up excuses to have us over. What would you think about trying to get her more involved?"
"You mean, try to get her to join in with us?" she asked.
"Well, maybe not all the way, or maybe not even with both of us. Maybe just you, maybe just me. I don't know. I just get the feeling the hotter we get her, the more she'll be willing to do to keep things going," I said.
"Well, that stands to reason," she agreed.
"So, what do you think?"
Jill started to giggle and said, "I was thinking something along those same lines, but wasn't sure how you'd take it. Haven't you noticed how I've been talking to her?"
Now it was my turn to laugh. "Indeed I have and that's what really got me going on this whole thing." We both laughed.
"I guess we should just play it by ear, but I think we could try spicing things up a bit to help her make her decision," Jill said. The next time Amy came over, we decided to turn up the heat.
We didn't have to wait long. Amy came over the next day, arriving around two o'clock that Sunday afternoon. She carried with her the now-familiar black velvet, drawstring bag containing her dildo and vibrator, and a bikini in one hand. She acted a little frustrated and anxious while we sat in the living room and talked, as well as while we laid around the pool. I think she was actually very horny and couldn't wait to get things started. We finally went inside a couple of hours later, when my cock had formed a mountain in my swim trunks from checking out both of my sisters in their skimpy bikinis.
This time we went up to our parents' bedroom, something we hadn't done before. They had a king size bed, and the room itself was larger than any of the other three bedrooms. It also had an attached bathroom with a huge tub. Amy was the first one out of her clothes and was dragging a chair over next to the bed while Jill and I kissed and disrobed.
We broke our kiss and Jill turned to look at Amy. "You want to see me suck his big dick?"
Amy nodded slightly and Jill smiled as she dropped to her knees in front of me. Jill took my hard cock in her mouth and began sucking while Amy rubbed her pussy. Soon though, we heard the familiar hum of her vibrator. Jill and I had grown accustomed to Amy's pattern of moans and groans, and we could tell she was already nearing orgasm. I watched as Amy threw her head back and began to shake all over while her juices squirted from her puss. That sent a jolt of electricity through my body and my cock twitched as I shot a load of jizz down Jill's throat.
