Cindy had to figure out what made Tanya grow, but she needed more time. She ran to the bathroom and closed the door, taking the Height (+) potion with her.
Cindy called to Tanya through the door, saying "Just a second, I need to use the restroom".
She frantically looked around the room for any clue to her extra growth. The floor was wet; Tanya was always so messy! She examined the water. It didn't feel any different and she didn't notice any unusual odors or colors. She looked in the shower - she had used a body wash and shampoo, but a quick glance at the back of the bottles didn't reveal any unusual ingredients. "Cinnndy!!" Tanya called insistently.
"Just a second!!" Cindy replied angrily. She was out of time, and she still didn't have a clue what was going on. Maybe it was due to differences in the physiology of their bodies, a result of Tanya's vigorous exercise regimen and frequent sports activities. Cindy thought about her options. She could spray herself again; it had worked once before, and she could probably bluff her way through any odd questions. At the very least she would still be taller than Tanya and could possibly intimidate her with her size if things got rough. Although a shower seemed to work for Tanya - maybe she needed to take a shower herself and see if it had the same effect. She could always spray herself after the shower if it didn't work.
She was about to start the shower when another thought occurred to her. Maybe the changes occurred in pulses; She didn't remember the man telling her how long it took for the effects to kick in, only that they just lasted for a few hours. She thought she used an equal amount of liquid on each of them, but in her excitement she was not sure exactly many times she had squeezed the bottle when spritzing. Maybe she gave Tanya an extra dose and it just took a little longer to kick in. Maybe it was just time to confess to Tanya. She was her friend, and the man did say that the effects were temporary.