In one move she slid off your pants and brought her head down to your waist, only to be hit in the face by your half-hard member, which was much bigger than the two of you expected. Your girlfriend was ready, quickly took a measure tape from her purse and measured your dick, seeing that at the moment it was 24 inches and kept growing as it got hard.
For a moment you were afraid of your girlfriend's reaction since she no longer has a bigger dick than yours, but she seemed to like it and soon she kissed you and started to caress your cock in the meantime. Your new cock was much more sensitive than before and continued to grow towards full erection, which was helped by the tip of your girlfriend's hard cock lodged between your breasts.
When you felt that your dick had reached full erection you broke the kiss and said "What did they do to me? My dick is very sensitive and I have never been so horny before." Your girlfriend was also impressed not only with the size of your dick but also with how much it expanded just from getting hard, she did not resist and measured again with her measuring tape, confirming that your member has impressive 35 inches and the thickness of a soda bottle in this state.
"That's what I call massive. I don't know how you didn't pass out, it must take a lot of blood for an erection of this size." your girlfriend said and you agreed, noticing that you didn't feel any problems other than the immense desire to feel pleasure. Your girlfriend tried uselessly to suck your cock, which was clearly not possible, as was having her being fucked by the monster between your legs. The way she found that was most effective was to hug and rub her entire body, with your cock passing right in front of her and the tip reaching just above her head. While your girlfriend was rubbing your dick you could feel her dick, which was tiny next to yours, rubbing against yours, just as your ballsack (from which the testicles had grown to the size of basketballs) was hit by her balls. You helped by stroking the solitary tip of your cock above it, but your new cock was too sensitive and you couldn't take it long before you came. Bulky jets of cum came out of the end of his cock, hitting the ceiling hard and splashing all over the place.
After 5 minutes of cum, your orgasm finally stopped, your girlfriend having her orgasm in the meantime. You wanted to get ready to go to the class from which you were already late, but there was no way. Analyzing the damage you had done you saw that there was cum everywhere, including on you and your girlfriend, not even the stall partitions had been enough to keep the the whole bathroom from getting dirty. As if all that wasn't enough your dick was still rock hard.
"That was incredible. I never imagined that an orgasm could be so intense." you said
"And I don't believe that you still want more. Your monster really has a lot of energy." your girlfriend said
Despite what he said, your girlfriend was clearly in the mood to continue as she was also still hard. Curious, she decided to compare the size of your dicks, looking at them in several directions, until it was time to compare the tips.
She took the maximum distance she could get in that stall, which barely left enough space for you to touch one end to the other, and in doing so she started to joke saying "No, the giant monster wants to eat my meat stick." laughing and rubbing the tip of her cock against yours, when unexpectedly the tip of her manmeat entered your urethra, much to the surprise of both. "Very interesting." she said and started pushing it further and further in, until you had her entire cock inside yours.
Your girlfriend looked at your face, in which you showed how much you loved the feeling, and without saying she started pulling her dick almost everything out before pushing it in again by fucking your dick, meanwhile you used your hands to stimulate your member outside. This time you resisted more and your girlfriend came first, allowing you to feel her cum running over your dick and end up in your balls. When her orgasm ended she was already satisfied, she took her cock out of yours, which was already on edge and you came as soon as the tip of her cock left your urethra. The first jet of cum that came out of your cock hit her hard, so hard that she lost her balance, making her hit the stall door breaking its hinges and making it fall. Even after that you continued to cum intensely, with both your cum and that of your girlfriend being shot by your dick before your orgasm ended, finally leaving you satisfied, at least for now.