It started when I joined a new gym. I had been a runner my whole life, but my girlfriend, Ava, told me I'd be "so much hotter" if I had some muscles and bought me a membership in a boxing gym.
It was true, I was always on the thin, lithe side of athletic. I stand six feet tall, and at the time I had no curves, either soft or firm. The prospect of losing some speed in exchange for a more versatile fitness and shapelier form excited me, and I made sure I arrived for my first session early.
It was obviously a place that got results. Most of the others in the locker room had defined muscles, and those who didn't seemed to be sporting new equipment. I pulled on my tank top, laced my loose shorts shut, and walked into the dim, yet noisy, gym proper to meet my trainer.
She greeted me with a snort. "So you're the bitch who's assigned as my first student. A wispy, flat-chested punk who thinks that just because she can run, she can fight. This is a long way from fashion week, honey," she snarled as she tugged on the long braid running down my back as I yelped in pain.
I hadn't expected that. Usually trainers took on students and tried to improve them, make them winners. This woman already seemed to want me to fail. She looked me over like someone buying a used car and I felt her judging gaze.
Of course, this gave me ample opportunity to do the same. Considering her skin and vigor, she was in her early twenties without a doubt. She was shorter than me, but had rippling muscles across her olive skin. Her near-black hair was in traditional boxer-braids, and despite being a trainer in a gym, I could tell she was wearing a deep red shade on her plush lips. My mind began to wander to how she'd look for a night on the town.
"Get on the floor and start doing pushups," she barked. Instinctively, I complied, dropping to the bare concrete and doing as told. After a few, she placed her foot on my back and started pressing. When I collapsed, her voice came at me again.
"Well, you're not as pathetic as you look," she said in a voice that was almost complimentary despite her foot still stamping me into the ground. "My name is Bella, but you will address me Miss. And until you win your first match, you're nothing. Understand?"
"Yes, Miss Bella," I replied, as though it were perfectly natural for this exchange to happen. Any other time, any other place, I would be giving this woman a piece of my mind, but she exerted an unknown force over me.
Miss Bella changed her stance, if only to use her foot to roll me onto my back. I laid there staring into the darkness overhead, wrapping my arms around my chest as though I could protect myself from the powerful woman. She then placed her foot on my belly, obviously showing how beaten I already was.
"Good girl," she condescended. "Now, your girlfriend enrolled you in a boxing/MMA hybrid course. If you keep this attitude up, you're going to lose every time. You've already got speed, and you're built to reach, so let's make you a winner." She removed her foot, offered a hand, and helped me up. "You're a lot tougher than you think."
By the end of our session, Miss Bella had taught me several simple combos, how to keep my feet moving, and how to keep my hands up at all times. Despite her intense introduction, she was a capable and firm leader.
When I was home, I told Ava that my new class was perfect. I kept quiet about the fact that another woman had dominated me so publicly, which was strangely arousing. All I admitted was I was looking forward to my next session.
~~~~~~~~~~~~~~~
The exhibition bouts of the newcomers were three months from my start date, which meant Miss Bella quickly became a major figure in my life. She had decided to set my training to five days per week, and even dictated what I would eat. She was powerful and confident, and in time I had grown attached to her.
It was late one night after an intense sparring match that we were in the locker room at the same time. I tried and failed to avoid watching her strip off her sweaty workout clothes. As she peeled away her sports bra, her surprisingly perky, large breasts exploded into full view. Then, her eyes met mine and I looked intensely at the floor.
In a second, her painted toes were decorating my view of the old tile, and her voice coolly asked, "See anything you like?" I darted my eyes up to her face, registering that she had removed her outfit and was standing before me completely bare. "I have a proposition for you, if you're the sort of girl," she continued.
I barely squeaked, and she laughed.
"I'll let you ogle me, pet me, kiss me," she paused, emphasizing the next word, "if you are entirely my bitch during your training. You obey my every word. You bathe me, you cook for me, and you sleep with me as I demand."
"That sounds so hot," I whispered barely audibly. But she heard it well enough, because the next thing I knew, she had placed my hand on her bare, sweaty breast and kissed my forehead.
She then went to her bag, rifled through, and threw some things at me. "This is your new uniform," she said confidently. "Wear this for our session tomorrow if you agree to be my slavegirl." With that, her firm buttocks sashayed into the showers, and I walked home without changing.
Ava was asleep when I got in. Guiltily, I looked at the things given over to me: a soft, black bralette and stretchy red compression shorts. Nothing else. I brought them with me into the bathroom, locked the door, and started the water.
I pulled off my grimy workout wear and struggled to pull on the tiny pants. Despite being name-brand and highly elastic, they exaggerated all the things they were meant to hide. Anyone who would look at me would easily see cameltoe! I also noticed the hems on the legs were unfinished, meaning they would slowly disintegrate until almost nothing would remain.
The top was a little easier to put on, though not much. My chest had grown both due to an increase of muscle and the slowdown in my running, and this was the size of everything else I had worn until now. My small breasts looked larger in the strip that wrapped them, and the thin fabric refused to hide my pointing nipples. The stringy straps that crisscrossed my upper chest and back didn't even contribute to keeping it up, but had a nice 'bondage-y' look to it.
Taking stock, I looked like one of those 'Foxy Boxers' the gym hires for all the neanderthals to ogle during down time, and I liked it. I imagined being in one of those bouts, completely losing to my opponent, and letting her have her way with me in front of everyone. And it was Miss Bella the whole time.
Shaking my head to clear it, I stripped off my new uniform, stepped into the shower, and cleaned up. Once clean, I dried hastily and pulled on my silky pajama bottoms, slipping into bed, spooning Ava.
"Love?" I called to her in the darkness.
"Tomorrow. I've got a headache," her sleep-stupor replied.
"Would you mind if I slept with my trainer?" I asked.
"Why would I care? I'm already sleeping with your sister," her overly-honest sleep self responded.
