Every time my spouse and I have sexual intercourse, regardless of whether or not I use lubrication, I always experience a burning, stinging sensation on my labias afterward that will last for up to a few hours. I have been with the same person for 5 years, we have no STDs, and we are not 'rough'. Occasionally the lubrication itself will even sting, regardless of brand/type. What is going on, and how can I stop the stinging? This problem is straining our relationship because although we may want to do it again later, I have to wait a few days before I feel comfortable enough to go through the experience again.