Go home early.

You hastily clean yourself up and head home early, avoiding Gemma as you do so. When you come to work the next day, you sit in your office, unable to do any work out of the dreaded moment that Gemma is inevitably going to walk in. You can hear her outside, playing the part of the dutiful personal assistant, answering phone calls, typing away at her computer, and thankfully not bothering you. It's just before lunchtime that you hear the familiar click of your door - no warning knock of course - and in she walks, in a pair of high heels and a tight black dress. Without a word she comes around to your side of the desk and looks down at your pants, eyeing off your groin with a devilish grin and a twinkle in her eye.

"Already hard," she smiles, looking at the raging erection beneath your pants, "Good boy."

"N-no Gemma..." you stammer as she reaches down and unbuckles your pants. Despite your protests, you let her pull your pants down to your knees, with your cock popping out and standing at attention.

"So pretty..." she murmurs, reaching into her pocket and pulling out a shiny black cock-ring. "Even prettier with some jewelry."

She slips the ring over the head of your cock and down to the base of the shaft. You can feel your cock throbbing as the blood pools in your shaft.

"Oh... what a tight fit," she purrs, running a single fingernail up the underside of your shaft. "I don't think I've ever seen your cock look this big..."