Don't stop stroking. Don't slow down. And don't cum.
Feeling desperate? Frustrated? Good. You've spilled your last drop of cum in this office. You can either get the hell out and try finding another job with "sexual harassment" listed as your cause for dismissal, or you can give me complete control of your little dicklet. I decide when and how you stroke, and whether or not you get to cum.
Think about it for as long as you like. You can stop stroking once you've made your decision.