Not two minutes after we started, we hear voices on the trail. From the sounds of it, it was someone walking their dogs. My girlfriend stopped suddenly and her eyes widened as she could see the man and his dogs on the main trail. They had passed right by us without even knowing we were there. After they had passed, I began rocking my hips, rubbing my cock against her. She laughed and said that was a close one. I grinned and she eventually returned my thrust with her own. And then something unexpected happened. As we were in mid thrust two teenage boys on bikes started down the path we were on at a decent rate of speed. Their bikes made very little noise as they approached. We both quickly looked to the side when we noticed them 20 feet away. There was no time to pull out as they were already staring at us. My girlfriend's face turned red as she looked away and down to our laps. I was laughing a bit as the boys rode past us, their gaze not coming off us as they slowed to ride past us. They stopped at the other end of the path where the trails reconnect and seemed to be talking and glancing our direction every couple of seconds. My girlfriend, still blushing, asked what they did when they rode by. I told her they just stared at us and joked that I should have flashed them her ass by pulling her skirt up as they passed. She continued to blush and agreed that it would have been funny.
I rocked my hips slightly, enough to grind my cock deeper into her pussy and asked if she wanted to finish. She glanced towards the boys who were still standing and talking and nodded yes. He juices were now soaking my pants where she sat. I guessed our situation was turning her on even more. She began to ride me harder, her body bouncing on my cock in pleasure. In the rush of it all, I slid my hands under her tank top and with one motion, pushed the shirt and bra up over her bouncing breast. I leaned my head down and began to suck on one of her hard nipples. While my hands slid back down her sides to her skirt, that of which I pulled up to her waist and placed my hands on her ass. She moaned slightly as I bit her nipple, causing her to lean back and place her hands behind her, on my knees, a fire buring in her eyes as she fucked me harder. Her hips bucked wildly as she started to cum on my cock, setting off my own thrsting as deeply as possible into her as I too began to cum inside of her. She leaned forward and collapsed her chest to mine and quivered as my cock jumped inside her, emptying everything I had into her.
Breathing heavily, she suddenly became aware once again that we were being watched. The two boys stood beside their bikes staring at us, a look of shock and arousal on their face. My girlfriend laughed shyly and waved at them before sitting up straght and pulling her bra and shirt back down. I sat under her and watched, completely drained of energy with a grin on my face. She stood up slowly on shakey legs and pulled her thong off. She tossed it on my chest before adjusting her skirt and pulling it back down over her legs, covering the cum that was now covering her thighs. I stood up and fixed my pants, putting her thong in my pocket and we slowly walked back to my car. As we walked passed the boys, they were silent and blushing, watching my girlfriend as she passed. Once we were about thirty feet from them, my girlfriend flashed her ass at them as she walked. One last look for the road. We returned home and after a hot shower, we spend the rest of the day laughing about our experience and vowing to do it again.