Dave in Janet's body was walking back to his old office as fast as she could trying not to look too suspicious. He was thinking about the great mistake she made... Switching bodies with his secretary and then leaving the magic pen with his old, now more lecherous body. That could end in a disaster.
The small heels of his shoes were clicking with each step he took. He still couldn't get used to that. Neither could he get used to the way Janet's smallish B-cups were jumping up and down tugging the skin on his shoulders and neck with their weight.
He was almost there. But a couple of meters was between him and his old office with Janet in his old body and the magic pen. And then, suddenly, he felt he turned back and started walking towards Janet's desk instead. He didn't understand what happened. He still wanted to go to the new Dave and get the pen back but somehow... His (well, Janet's...) body simply wouldn't listen to him. He sat by the desk, straightened his shirt on his tummy noticing how tight Janet's waist was, took some documents out of the drawer and begun filling them in.
Dave inside the secretary's body wondered how is it that even though he wanted do do something else and that he even didn't know how to fill in those documents, his body was still doing it. It felt like if it was on autopilot... And then it hit him.
"It must be Janet in my body!" he thought, "She used the pen!". He was devastated. He didn't manage to recover the pen and now it was the new Dave who had control over it...
And he indeed was planning to use this control more...