Continue to part 2.............
The head of my cock was out for the most part it was merely parting her sweet pussy lips at this point but not enough to throw off the aim. This was another mistake of ours although, it might not have mattered much. Since my cock had not completely dislodged itself it did a great job plugging Nara's pussy, nothing leaked out. The problem with this, if we had just stayed balls deep after I came in her we could have possibly finished the ride with nothing else happening but, since we had attempted to dislodge ourselves this let all my cum flow down her vaginal walls fully lubricating her. Although I had gone in nearly dry, except what ever water we had from the pool, from here on it would be a smooth ride.
This all happened within a few seconds but there was a lot going on. After Nara had attempted to pull her self off of me and, we had come so close, she was pushed. After all when over crowded, people do not simply let others push them around. They tend to push back and back down my rod she went. I know she was frustrated but this was not going to stop her. She tried again and did not even get off the head of my cock the second time before getting pushed back down. She tried a third time and by the fourth time it was clear she was losing ground. Every time she tried she made less progress then the time before. On her fifth attempt she only got about three fourths the way off and by the sixth attempt she must have realized what she was doing and what was happening. She was now fucking me unintentionally while trying to get her self free. Once she realized this she froze and tensed every muscle in her body in attempt to stop any movement. Oh, she was angry she would have to ride this out with my cock fully impaling her until I went limp or else she would end up fucking me in a vain effort to get free. Nara had decided on riding it out.
"You fucking bastard", Nara whispered venomously, "you are so dead".
"Not my fault," I pleaded "how could I have known?"
"You did not even try to get out of me."
"Yes I did". This was true I had tried to get out of her although I do admit I might not have tried as hard as she had except on that first attempt and I had stop trying to help altogether by the third one once I knew it was not going to work. She had been the one who kept trying and now she was sitting on my cock squeezing it as hard as she could with her pussy just to keep it from moving. I was still at full erection but the unintended fucking and the squeezing of her pussy were doing nothing for calming me. In fact I started to feel myself building up again as the drive continued. Despite her best efforts we still had grinding and a bit of up and down movement just from the crowded car and the road. After several minutes Nara was getting tired and her vice grip started to slip for moments and then we would have all kinds of movement. Although small I am sure when you are trying not to move at all even the smallest movements feel huge. In these momentary lapses in grip I would get spikes in pleasure and panic. I was building up again and was going to cum in her again. The second time would be worse because this one would be driven completely by fucking my sister not an accident.
It must have been during one of these lapses in my sister's grip when she started getting pleasure too. Although not intended on her part either. She fought with herself to keep from cumming as well. She tried to hold us locked in place as best she could but just could not keep the pressure up long enough to stave off the inevitable. Then we hit the hills.
We did not see them coming and honestly we had both forgotten about them with our minds on trying not to cum into each other and all. The first hill when we it hit gave every one in the car a surprise except for the ones up front who saw it coming. For Nara and I though it was a whole different experience. Have you ever had butterfly's in your stomach when having sex? Probably not but I will tell you it is amazing and terrifying. That first hill gave us two full length strokes we could not have stopped even if we wanted to. I know this because we did try stopping the strokes. My sister tensed up again and I tried to press my self into the seat. It did not help. It was pure pleasure for both of us although neither of us wanted it. The second hill was not a surprise but felt even better then the first. We were now fully fucking because of these hills of joy. There was no stopping it, up and down. I was getting dangerously close to cumming and there would be no chance of stopping it. Nara it turns out was in the same situation. She had been fighting back her orgasm for a few minutes and these hills were too much. I was about to cum for the second time in my sister's tender womb and I did not know if I should warn her or not. Would it make any difference if she knew I was going to cum or not? After all either way I was not going to be able to stop it. I decided against it figuring she would be too angry. Better to just ride it out. On our last hill I could not hold back any longer and exploded into Nara's pussy for the second time in the last 30 minutes. I am not sure if my second eruption into my sister is what put her over the edge or if she just could not hold back any longer either but she came right after me. I know she had an orgasm and a powerful one because of how she was shacking. While I was pumping wave after wave of cum into her juicy womb I felt her vaginal walls clamp down and start trembling meanwhile her whole body was shivering. I was not the only one who noticed her reaction.
"Are you alright there Nara?" inquired Jessica.
"Oh, I am fine," Nara breathed "just a sudden cold spell I'll be fine".
"Oh, alright, well we are nearly to your place. You two are going to be the first ones out you know," Jessica replied.
I had forgotten about that. We would be the first ones out because of our location in town. They would simply drop us off at the house. No need to go back to the school since this route would go right by our house. I am not sure if Nara was concerned or not. She did not seem to care about anything at the time and was still riding out her orgasm. Although her body had stop shivering her virgin would still have tremors every few seconds. There was some good news at this point at least. My cock had finally started to calm down slowly growing limp. Although my cock never left Nara's pussy until we arrived home, it was fully flaccid once we did. I am not sure why but after her orgasm and once I had gone limp, Nara was either too tired, felt too defeated, saw no point in it, or maybe some of all of the above but, she did not try to get off my cock once after her orgasm.
Once we arrived Jessica opened the door and hopped out only too eager to stretch. Nara kept her legs together as much as possible and covered her crotch as discreetly as she could with out drawing attention as she pivoted on my flaccid cock that was still lodged in her pussy. She got up slowly and now that my hands were free I was ready and was able to stuff my cock into my swim briefs without anyone seeing a thing. It was probably just as well that we had not separated since it kept most of the fluids in. As Nara got up I got a view of her pussy briefly and saw it dripping. Nara was quick here though and covered her modesty with her hand and moved the fabric back into place while catching the dripping cum. We had done it. We managed to get out of the car without leaving a trace and no one seeing a thing. We got our things out while the rest rearranged themselves with the newly vacated spots. Soon they were packed in again and we waved our good byes.