Rainbow in your Mom's body looked up at you expectantly. She moved to sit, but her pant-skirt making a tearing sound, and it fell to the floor, revealing a purple thong. Now she sat more comfortably. This sure will be an interesting experience...
You get down on all fours like Rainbow and walk around to the back of her and start sniffing. Rainbow curves around and does the same, starting to pant loudly. She moves to take her shoes off, revealing her small feet. Then she starts to scratch her thigh, where her thong strap was, and, miraculously, it fell to the bottom of her knees. She then turned away from you and started panting heavier. Guess the hormones run differently with a dogs brain. You pulled down your pants and stuck your hardened cock into her vagina from the back, a feet few humans had accomplished. A half-yelp, half-moan came from your Mother's lips, and continued to do so as your pounded her forwards. Somehow she was able to stay upright during all of this, her face remaining rather monotone besides her mouth being wide open and making noises. You finally let lose your lode after an entirety of pleasure, and she kept it all in by clenching her clit really hard. She rolled over onto her side and you pulled your pants back up, satisfied with a job well done.