Shedding can happen anytime surrounding an outbreak - typically you will learn what it feels like before you actually see an outbreak. Personally mine starts with just a random pinch feeling, then it itches, then the outbreak occurs. The pinch and itch is daaaays before the OB. So if you are concerned about shedding during sexual activity then you should start taking antivirals days before you plan to get busy to make sure any potential shedding is knocked down by the meds

Viral shedding with herpes can vary in duration. Typically, it can last for several days, ranging from 2 to 12 days on average. During this time, the virus is active and may be contagious even without visible symptoms. It's important to practice safe sex and take necessary precautions during this period to reduce the risk of transmission. If you have specific concerns about viral shedding or managing your condition effectively, consulting a healthcare provider would be beneficial for personalized advice and guidance tailored to your situation.