Already extremely aroused by what had happened so far and the mixed smell of latex and female juices, Jenn had to gather all her willpower to resist Susan's pleading but she already knew it was a lost battle. One more desperate look from Susan followed by a low "Jenn, please..." was enough to make Jennifer succomb to her own lust.
She began to remove her clothes while moving toward her friend. Once naked she stepped between the strange balloons that once were Susan's legs and kneeled to face her friend's enlarged pussy. Jennifer darted her tongue and began teasing Susan's clioris while she let her right hand explore the black vulva just below. Susan, feeling the fingers just at the entrance of her vagina, pushed against them, hissing a "Come there" at the same time. Jennifer smiled and let 3 fingers slide inside her friend while her tongue played with her clit. Before long, Jenn had a fourth finger inside Susan's pussy who shivered with pleasure before moaning "More.." and pushing against her friend's hand. Jennifer looked with fascination has Susan's pussy opened and accepted her thumb with ease and finally engulfed her hand.
Jennifer was getting very horny and litteraly kissed and sucked Susan's clit while pushing her hand inside her. Lust had taken over and the two women gave in with pleasure. In no time Jennifer had her arm past her elbow inside Susan who was still begging for more. Like in a trance, Jenn let her second hand come to Susan's pussy and began sliding it along her arm. The brunette's vagina stretched once again and welcomed this second intruder with few resistance. A few minutes latter Jennifer was fucking Susan with both arms, going past her elbow and furiously licking her clit. And still the brunette wanted more.
As Jennifer was considering to go shoulder deep, she felt something warm and soft bump against her ass. She turned her head to see and looked in awe the transformation Mrs Perkins had gone through. Her body was now covered with latex and her slick skin shiny black. Her upper body was like a doll or manequin, her face featureless. From the waist down the changes were more drastic. Her legs had disappeared or had been engulfed in a large mass of black goo. It made an ovoid horizontal shape and she was resting on it like some sort of snake or slug. Just as Jennifer was wondering what had exactly happened to her, the front part of the bulge opened, forming vertical lips and it dawned suddenly on Jennifer, Mrs Perkins lower body was her gigantic vagina.
Too stunned to react, Jennifer looked as the woman cam close to her and her pussy opened to swallow Jennifer's ass, then her legs and her waist. Jennifer could only moan has the felt the soft warmth of this incredible pussy engulfing her and before long Mrs Perkins had gone far enough to have swallowed Jenn up to her breast. The young woman was lost in lust, her arms were deep in her firend while her body was in the warm confines of a giant vagina, juste her head remained free. That's when she felt her whole body tingle, announcing a change.
(Feel free to continue, be inventive)