In my experience—though not during sex—while I was reading BL manga (alone in my bed room), I heard a whisper "What are you doing?" I replied, "I'm reading BL manga; why? Do you want to read it too? Here, I'll show you." I found some smutty BL manga and scrolled through it rather slowly so the ghost could read it properly. After that, I was never bothered again.
The uke PRACTICES THE BLACK HOLE TECHNIQUE, seme think that while drill in (╯°Д °)╯╧╧