In "The Spectacular Spider-Man" #32 (July 1979) the hero probes the "House of Darkness" with a light mounted just above his crotch.
Fun fact: I have this idea for a "spotlight dance" belt buckle that combines the spider-signal with a "dance ray" utilizing the rare element Tarantellium. Just train the light on a bad guy and shout out a dance style (like the Hustle or the Shurg) and they have to do it. It would be a great gizmo for a hero with a name like "Captain American Bandstand" or "The Soul Trainer" or maybe a super-group called "The Party Machine with Nia People." I've got a prototype model but so far all it does is cause dangerous epileptic seizures and severe retinal damage. (Again, Jeremy, I apologize.)