Sasha's boss is a bitch. Let's start there. From day one of Sasha's new job as a graphic designer for the silicon valley startup Futanarily™, her boss Bridgett has been treating her like an intern. Instead of putting Sasha's talents to work, Bridgett sets her about menial tasks like ordering office supplies and going on coffee runs. The older woman is clearly envious of Sasha's stunning looks, and misses no opportunity to ridicule the young futa. Sasha could tell Bridgett must spend a fair number of hours at the gym each week to keep her figure, but Sasha didn't know if Bridgett was a futa herself. And the fact that she couldn't tell meant Sasha almost certainly had a bigger cock, because even when she wasn't hard... it showed. Skirts don't do much to hide a bulge too big to tuck.
When Pumpkin Spice Season arrived, the coffee runs became a daily mandate. Bridgett orders her lattes "extra pumpkin spicy", even going so far as to threaten to send them back, should they not be sufficiently extra pumpkin spicy. Which actually happened the first time. Which was the last straw for Sasha. She decided to take out her pent-up frustration on the latte.
After actually making the embarrassing request for an extra spicy coffee, she got a second empty cup from the barista, and when he wasn't watching, poured out half of the first. She could easily fill a full cup but she figured half-coffee, half-creamer be enough for flavor. It was a Venti after all.
Tempted as she was to conduct her mischief in the coffee shop bathroom, Sasha restrained herself for the 2 blocks she had to walk back to her office. She ducked into Bridgett's executive washroom and locked the door to rub a quick one out into the half-full coffee. When it was full, she used the second cup to catch the rest of her seed, filling the Venti-sized vessel three quarters full before she was satisfied.
Pleased with her little revenge, Sasha snapped a selfie in the washroom mirror, expecting to send it to Bridgett as a sweet parting shot after she was inevitably fired. Much to Sasha's surprise, Bridgett loved the salty-sweet concoction, and demanded she produce another like it, every morning henceforth "for the rest of her internship"... which as far as Sasha was concerned would be the rest of Pumpkin Spice season.