Sorry if you’ve just eaten your lunch, or if you’re feeling hungover (or if you’re all of the above), but we felt compelled to show you this disturbing footage from Madonna’s concert in Lisbon.Who in their right mind would willingly pay to watch a 50-year-old woman repeatedly thrust their spandex-clad groin against a guitar? We feel violated on behalf of that guitar and cord-based instruments throughout the world. And watch out for what happens at the end of the clip. Serves her right…