We ate and sat and talked for a good 2 hours. I was so in heat.. i wanted him so bad by this point. I knew that Debbie had relatives in town and most...likely she would be home, so we rode out to the cruise strip. Up and down several times with no excitement, he turned off the road. Telling me that he was going to take me and show me his "spot". We drove about 2 miles off the road and up a dirt road and parked beside some abandoned railroad tracks... at least that is what we thought. We started. We sat there for a moment just enjoying the feeling and then I felt the slow withdrawal, and advance, again, slowly, and then it began to get a little faster. I was already on the verge of cumming again, when I felt that strange situation come over me as if everything wants to be pushed out. Normally, I fight it back, overcome the urge, but his cock was inhibiting my ability to do so. I tensed, my asshole gripping his shaft, then at once I released, I began to convulse hard as he continued to. I squeezed my throat muscles as hard as I could, while maintaining a lip lock on his head. Mark just muttered “oh fuck”. I looked up at him with those puppy dog eyes, and shot him a grin. After nearly 20 minutes of sucking Mark's enormous cock, he pushed me back on the bed, and told me to lye down on the bed on my belly. I did as he told me, and Mark quickly mounted me from behind, spreading my silky smooth thighs. Mark works up a big lugie, and spat out the snot and spit right into my hairy. "SHIT! SHIT! SHIT!" I cried as my cock began gushing inside of her."YES! YES! OH FUCK YES!" cried Donna loudly, as she felt her foster son filling her arsehole with his wet sticky load.I clung to the back of Donna like a rutting a****l, as I unloaded everything I had in her arse, and for several amazing seconds I pumped my load into my foster mother, as my foster father and sister watched.Then finally I stopped cumming, and so did Donna, and I just laid on top her catching my breath."Oh fuck!.