Test a (Weight Gain/Giantess)

"Would you be willing to be a test subject for a new **** my company is doing a trial on?" Marked asked. "It's safe. They have already tested it on 100 women, and in most cases, it has increased their breast size by one cup and increased their libido. "

I was a little shocked, not just because I had a cock in my mouth, but the thought of a more giant pair of tits and more sex; I would have to be a fool to turn that down. I nodded, and his cock spasmed, and he came, shooting a load into my mouth.

"I will be back in a moment; I just need to go grab the stuff."

Mark disappeared into the closet.

When Mark returned, he had a small cardboard box, which he had set on the table.

Mark pulled out a small vial of a pinkish liquid and a syringe, filling it with the ****.

"How does it work?"

"The dosage is one mL, injected straight into your buttocks. After a couple of days, you should start to notice changes. The changes are permanent, but they should be done after one week."

I pulled my jeans down and leaned over the back of the lounge, pulling my panties down.

"Do it."

Mark pulled the needle out of the bottle and pressed it against my arse.

"Oh, by the way, we need to monitor how much weight you gain."

Mark pushed the syringe and emptied the liquid into me, leaving a slight stinging feeling in my bum.

I decided to watch TV, my bum still stinging, but I soon forgot about it, and I was asleep before the end of the episode.

A week later

I had nearly forgotten about the **** trial, and even if I hadn't, Mark didn't mention it at all and didn't act like anything was different, but something was.

I was always horny, like more than usual, I would wake up with a hand in my panties, and spend the whole day wet. At work, I would sneak away and masturbate in the bathroom. Mark and I had an open relationship, and he allowed me to fuck his two roommates, Jason and Dillon. Also, I was hungry more often, so I ate large meals and snacks. Food tasted better, and even cum tasted better.

Four weeks later, my clothes didn't fit properly anymore. My bra was tight, and my B-cup breasts had grown into D Cups. My breast were spilling out of my bra, my pants were tight. I loved how it felt; I started to wear skimpier clothes to show off my body.