Andrew decided he would go home for the day as he felt his snake throb for every attractive girl in sight. With the two snakes in hand he went home. He got home before anyone else and did what every newly enlarged teenager would do. Measure himself. He grabbed a tape measure and went to the privacy of his room trying hard to not let his snake stand to attention before he measured it. First he estimated width at about 1 and a half inches and a bit with his head bulging out almost half an inch. He measured his length and whistled. "12 inches... no 12.3 inches... over an inch for every year!" He started playing with it. It started growing, mostly in length. It's width grew to 2 inches and a bit while it's length slowly increased. He heart was beating quicker and quicker. He measured it again eventually. "17 dot 3..." his penis throbbed. "17 dot... 18 dot 2 inches...." Andrew gazed at his massive erect python.
He heard stamping footsteps on the stairs and his adoptive sister Callie came smashing through the door. It hadn't been locked, the door didn't have a lock to begin with. "Andrew where the fuck..." she gasped as she saw his cock. "what the fuck... that dick can't be real... what the fuuck are you doing before dinner you..." Her eye caught the snake on the ground and her expression changed all of a sudden. She looked at his dick or rather she stared at it. She seemed hypnotized. Body wise she was overdeveloped for her age. She was two years older than Andrew with a very womanly figure at short stature. While she looked overweight in loose clothing her waist was not even what you would call pudgy. He chest measurement had made her out to be a E cup already but she insisted on wearing undersized D cup bra's or even C cups sometimes with the incorrect band sizes.
She pulled off her skirt an panties. "What are you..." Andrew stuttered. She started unbuttoning her shirt without answering he heard he presumably bra snap as she tried to pull the shirt off. Andrew had not thought his adoptive sister to be attractive before but now her lustful expression and slowly jiggling breasts as she approached him turned him on. "I want you... I want your cock..." Andrew didn't need to hear more and got up got around her and pushed her onto his bed. He tried to attack her her his erected python hastily as she was lying on his bed but missed with his length, rubbing his cock against her belly instead. "Put it in me." Callie moaned. This didn't help as Andrew cock rose pointing more upward into an even fiercer erection. He pushed his cock down and managed to get it in her. She didn't even complain when he hit her cervix she didn't yelp, cringe or twitch visibly. He couldn't go balls deep, he never expected to go that deep to begin with with this massive snake of a cock.
He started pounding her and she started moaning louder and louder he felt pressure start to mount in his balls. He changed position and grabbed her leg. He started his assault again. As he pulled out just a little too far his cock flew out and lifted up into the air as if attacking him it smacked against his chest. It was only a tingle of discomfort. He pushed it down and pushed it into Callie again continuing with what he had started. He started at Callie's mounts and thought how many of her classmates would dream to see them or have them as they bounced in all their voluptuous firmness on her chest. Callie started pinches and playing with her own chest as her moans became louder once again. As she pinced her right nipple a third time he could feel her climax as she got wetter and tighter while the rest of her body visibly relaxed. Andrew felt pressure mount in his balls then the base of his penis. His snake spewed semen into Callie's depths. He could feel it flowing through it's length and into her. He pulled out and fell onto the bed. That was amazing, he now had a sex slave of some kind thanks to the stuffed snake and his cock was ridiculously huge.