How to Do It Photo illustration by Slate. Photo by EyeEm Mobile GmbH/iStock/Getty Images Plus.  Our advice columnists have heard it all over the years—so we’re diving into the How to Do It archives to share classic letters with our readers. Have a question?   Send it to Stoya   and   Rich here.  (It’s anonymous!) Dear How to Do It, I’m a queer woman in my mid-20s and my partner is a straight guy in his mid-late 30s. We’ve been together for nearly two years and have a pretty good sex life (four to six times a week). We’re both poly but have been mostly monogamous. We’ve developed a standard sexual routine and he usually gets me off with his fingers. He is clearly committed to getting me off, though I sense it’s more of an obligation than something he enjoys. When we first started hooking, up he mentioned he wasn’t very into giving oral (which he doesn’t remember saying). That’s fine, I was still coming, and I enjoyed giving it enough for both of us.…