How to Do It It’s part of a bigger pattern. Photo illustration by chachamal/Getty Images Plus.  How to Do It is Slate’s sex advice column.  Have a question?  Send it to Stoya and Rich here.  It’s anonymous! Dear How to Do It, At my best friend’s wedding, her brother-in-law sexually harassed me when I was trapped in a car with him. I could tell you a long story with the exact number of drinks I had and precisely what he said, but it’s not as important as knowing that I didn’t want it and he persisted after I demurred multiple times. I confronted him the next morning and have made peace with his actions and my response. The problem is my best friend. This is a woman I’ve been close with for four decades, and she completely does not believe me. She’s told me I was too drunk to remember, that I shouldn’t have told her, and that I probably misinterpreted what he meant.…