BERLIN — The German government is rushing to integrate hundreds of thousands of asylum seekers, offering them language classes and the prospect of work. But in a country known for its matter-of-fact acceptance of public nudity and creative forms of lovemaking, it predilections and pitfalls of the European boudoir, Germany’s Federal Center for Health Education has gone live with a sexual education website for adult migrants. Using highly graphic diagrams and images, the $136,000 site outlines everything from first-time sex to how to perform far more advanced sexual acts. After a rash of sexual assaults allegedly committed by suspects including...