When Mary woke up, she initially forgot what had happened. She felt a tightness in her genitals, and sensed a small, soft body in the bed next to her. Then it hit her: "That's right. I'm a guy. This must be morning wood. And the girl is Jeff."
Mary rolled over, poking Jeff in the back with her cock, trying to prod her awake gently. "I used to hate when he did this to me, but now I can see why he did ... it's hard not to think about sex when you wake up with a boner and a hot girl nearby!"
Luckily for Mary, Jeff was soon awake, and retained the same level of horniness as a girl which he had as a man. Jeff was soon astride Mary, riding to several more orgasms.
But this time when they were done, Jeff got unexpectedly serious.
"Did you like this?" Jeff asked.
"Yeah, " said Mary.
"You liked sex as a guy?" Jeff asked.
Mary: "Yeah, of course, it was fun. It was a really interesting change."
Jeff nodded, thoughtfully.
Mary asked: "Is something wrong?"
Jeff: "No ... it's ... just a lot better ... as a woman, isn't it?"
"Well," pondered Mary, " We've both had it both ways now, so there's no use in lying ... yeah, a female orgasm is way better"
Jeff looked serious again.
"Hey, " Mary said, "come on, it's not like a male orgasm is bad!"
"No, " said Jeff, but sounded unconvinced.
Later that day, they reverted back to their original bodies. Mary jokingly announced to Jeff as her boobs grew back in, as her balls receded, as her vagina reopened, and finally, "there goes the last of my little penis, back to being a clitty, like a good girl!"
Jeff smiled weakly.
Mary was curious to try the other vials now that she knew the magic was real, but was hesitant, and also had to return to work soon.
Jeff seemed sullen the next few days, but Mary didn't think much of it. He generally got home before her, and after a few days, she noticed both the male and female vials were sitting out in her night stand when she got home. She put them away without comment.
The next day, the vials were in the box, but she thought her dresser drawer was open slightly. She checked, and could swear her vibrator was moved.
Finally, she decided to come home from work early, and quietly snuck into the house and up to the bedroom when Jeff would normally be changing out of his work clothes.
Mary heard the unmistakable sounds of a woman deep in the throws of orgasm, and when she peeped through the crack in the door, saw exactly what she thought she would: Jeff, as a woman, was fucking herself in their bed with Mary's vibrator. After cumming several times, Jeff lay in the bed for a few minutes, drank from the male vial, turned back into a man, and got dressed.
Mary hastily snuck back downstairs and pretended to just be getting home.
That night, she suggested they have a few glasses of wine at supper, to make the ensuing conversation a little easier.
"Jeff, tell me the truth," Mary asked: "Since we had sex with the genders reversed ... are you ... or do you ... do you want to be a woman now?"