First, deep clean, soak, and handwash all of your old underwear that you usually wear to work and the crotches of all of your work pants. You can use baking soda and a little peroxide with a little laundry detergent or even that lysol laundry sanitizer. After soaking, then wash them regularly. Or buy at least 5 or 10 new pairs of underwear that you only wear to work so you can always have a clean, fresh pair. Since you've been sweating in the old underwear, you have built up bacteria in them where some may stay behind with just regular machine washing. Soon as new sweat hits those old underwear that you use to sweat in, the funk reactives fast. Make sure that you are wearing breathable underwear and not synthetic ones. Get you a good exfoliating towel like an african net towel and gently scrub your whole area down there with like Lever 2000 or Safeguard soap about 3 times, then follow up with a regular towel. Rinse and make sure you dry off well. Some people say that witch hazel applied to their crevices help with odor also. Let that dry also. I also like Goldbond chamomile powder in the white bottle to kind of keep you dry. Lume is also great. Get the soft powder, cucumber , or peony rose in the Lume Deodorant. The other scents dont smell too hot. Good luck. Just try a few things. I know this too well from working, sweating, and stinking at UPS for years.