Now that her dick was bigger Martha was forced to buy new underwear again, but she would leave it for the next day. Already on the first day she woke up with a morning wood, her dick was so hard that the first thing she had to do was go to the bathroom and jerk off. Unfortunately she was so horny that she forgot to lock the door and stopped with a fright when Peter opened it and walked in. She ran to hide her erection from her son, taking advantage of being naked to pretend she was getting in the shower. Peter apologized to his mother for not realizing the bathroom was occupied, then took a quick piss and left. Martha then finished her handjob and in the end had to take a shower herself, to clean herself and the bathroom which she soiled with her cum.
Then Martha prepared breakfast and after eating she took Peter to school, where he intended to go straight to the mall to buy new underwear. That day luck seemed to be against her, because on the way to the mall her car died and no matter how hard she tried it didn't start anymore, which forced her to tow to a mechanic shop, where the mechanic found the problem but said that they didn't have the part she needed at the time, and she would have to go back for the car the next day.
After the mechanic shop she went to the mall by bus, but the vehicle was full. An unusual situation happened but she was so ashamed of what happened that she didn't have the courage to speak out. She had an erection and, even though she tried to avoid contact, she ended up rubbing her cock through her clothes on a woman who was nearby, making a sudden movement to get as much distance as possible and holding her purse in front of the bulge formed in her clothes. To make matters worse, the woman realized and knew that they had rubbed a hard stick on her, but she thought it had been a man who was next to Martha, who was slapped in the face without knowing what was happening. To make matters worse, her erection never gave way, so after she got off the bus she ran to the nearest public restroom, where she looked until she was sure no one was watching and entered the men's room. She locked herself in a stall and took her hard cock out of her pants and jacked off until she was satisfied, leaving the dirt behind as she slipped out of the bathroom.
She did her shopping without a hitch and as she exited the store she was met by Gloria, an old friend she hadn't seen since high school, who exited a nearby electronics store at the same time. She was also seen by her friend and they stopped to talk, catching up. Martha, after learning that her friend had been buying a new cell phone at the other store, told her about the problem with her car and that she was thinking of calling a taxi, She just didn't tell him about the experiment she was taking part in in the lab or its effects.
Gloria offered to give Martha a ride so they could talk some more. The single mother accepted the offer. On the way Martha found out that her friend was still single even though she wanted so badly to get married and have children. But Martha found herself analyzing her friend's body with, thinking that she was too attractive not to have found a husband yet, and then she was undressing Gloria in her thoughts.
Realizing the kind of thoughts she was having Martha felt that her cock had become hard again and, looking down, saw that the bulge formed by her erection was very obvious. She tried to hide it, but Gloria had seen the bulge and stopped the car, saying she thought she was going crazy as she had seen the bulge of a hard cock in her clothes. Not wanting to lie to her friend, Martha told her everything, but Gloria didn't believe her before she allowed the other woman to touch her member.
After that, everything evolved almost without control. They continued their trip to Martha's house, where Gloria insisted on going in as well, as she was very curious and wanted to see her friend's dick, which after much insistence she left and undressed her bottom in front of her old friend. And things ended up evolving so that in the end Martha ended up fucking Gloria.
For the remainder of that day and the rest of the week Martha noticed that she was having erections more often, and she believed that this was not just because of the size of her cock, but the experience of having fucked a real pussy had been so good that she wanted to do it again. She called Gloria, as she got her contact information after the last meeting, and they arranged to meet again the day before the next test.
On the agreed day, Martha left Peter at her mother's and went to meet Gloria. They spent a moment together and had sex again, in the meantime Gloria took a strap-on that she had arranged and put it on to fuck her friend's pussy.
That's when Martha remembered that she had been getting so used to having a dick and focusing so much on it that she had completely forgotten about her own vagina. It was only then that she discovered that her balls had grown so much that there was no room left for her vagina, which had been completely replaced making her a shemale now.
That night Martha and Gloria watched some TV together in Gloria's living room, where eventually she fucked her friend one more time and, eventually, she ended up sleeping in her arms and with her dick still in her friend's pussy.
The day of the next testing session Martha woke up late, her cock was painfully hard but she didn't have time to deal with it. Gloria helped her get dressed, leaving her without underwear under her skirt, making it easy for her to jerk off in her friend's car on the way to the lab.