I know exactly what you mean. Sometimes one of my family will walk by while I'm watching an anime, and suddenly from out of nowhere it gets all pervy. I'm like "No really, I do have good tastes. This show Was decent before this..."
Happens all the time. One minute I'm sitting there watching a totally clean anime and then suddenly one of the female characters starts groping another for no good reason and the girl starts half moaning. Suddenly, laying on my bed watching it on my computer screen from a distance sucks really bad when I need to turn down the volume. Now I'm scrambling like I should be ashamed.