The door was cracked open just a few inches, letting out a sliver of light and the scent of laundry detergent. I stopped, my curiosity getting the better of me, and leaned in to see if she was actually using the machine or just playing music.
Inside, Emily wasn't running. She was standing in the center of the room, her breath coming in heavy, ragged hitches. She was wearing a pair of grey sweatpants that clung to her legs, but the fabric at the front was strained, pushed outward by a thick, pulsing silhouette. She had her hand slipped inside the waistband, her fingers working with a focused, urgent rhythm. Her head was tilted back, eyes closed, and her chest was heaving as she stroked herself, the bulk of her shifting visibly beneath the fabric of her pants.
I shifted my weight, trying to get a better angle, but my sneaker scuffed loudly against the hardwood floor. Emily froze. She didn't jump or scream; she just slowly turned her head toward the door, her hand still gripped tightly around herself. She caught my eye through the gap, a small, knowing smile tugging at the corner of her mouth as she looked down at the bulge in her pants and then back at me.
"Caught me, did you?" she asked, her voice a low, honeyed rasp that vibrated in the small space between us. She didn't pull her hand away or scramble to cover herself; instead, she leaned back against the gym bench, her chest still heaving. The grey fabric of her sweatpants was stretched to its absolute limit, the thick, pulsing shape of her twitching with every heartbeat. She looked at me with a mixture of amusement and raw desire, as if she had been waiting for the moment I finally stopped pretending I wasn't watching.