Every gay boy in the late 1970s knew teen idol Leif Garrett, whose two albums, Leif Garrett and Feel the Need, were getting gushing reviews in the teen magazines: the greatest singer who ever lived! And the cutest boy in the universe!
Or not. He was way too swishy, even in that era of androgyny, to be an object of homoerotic desire. But they followed him anyway, because he was the first gay person they had ever seen on stage. Maybe they weren't doomed to sad, lonely lives in the closet after all.
Of course, he wasn't openly gay. The teen magazines tried to push his macho interests, like skateboarding and cars, and interviewed him incessantly about what kind of girls he liked. But come on.
The penis you're looking at is called a club-bulge, an effect created by a combination of very tight pants and shoving a rolled-up sock down there. It was a standard accessory for every actor at the time, and still in use in gay clubs. Leif's is actually understated; you should see what Shawn Cassidy was wearing.