One of Harry's first rites of passage in his new life is to select a wand (i.e. penis). The wand/penis is the most important tool in a Wizard's arsenal (or arse) and so this scene is treated with great reverence and mystery. While experiencing Diagon Alley for the first time, Harry also pauses with a group of other young boys to admire a much coveted broomstick (i.e. long hard shaft of wood).
Harry's indoctrination begins in earnest when he is sent to a special school who purpose is to train him to use his wizard powers safely, while still being able to live in a world full of muggles. Young students at this school are forbidden from practicing "magic" (i.e. homosexuality) outside of the school (this is the so-called "restriction on the use of underage magic"). They are also forbidden from using magic in the presence of muggles, who might be frightened or angered by witnessing it, an obvious and heavy handed commentary on gay-straight societal tension.
The students at this school are segregated by gender, a clear attempt to encourage homosexual relationships. The most popular pastime at the school is a game called "Quidditch", which involves riding hard shafts of wood, handling several types of balls, and trying to score points by successfully penetrating the hoop. This activity is enthusiastically endorsed by school officials for obvious reasons. Harry quickly excels at this new game and quickly becomes known for his above-average broom handling.
Harry spends a great deal of time with Hagrid, the man-bear who first initiated him into the wizarding world, but also forms a close friendship with Ron, a fellow student (and first real boyfriend). The two also tolerate the presence of Hermione, a female classmate who compensates for her lack of a penis by being a better than average student. Together, this troublemaking threesome get into mischief on numerous occasions, causing consternation and concern among the teachers.
Ultimately, the story is about Harry coming to terms with the tragic and premature death of his gay parents, who both died from AIDS (personified in the story by a cliche evil villain named Lord Voldemort). Although both his parents were struck down by the horrible disease, Harry himself was spared (though it did leave him scarred for life, i.e. infected with HIV but not full blown AIDS). Harry desperately searches for a new father figure to fill the void (either figuratively or literally) left by his father's absence. Harry first clings on to Hagrid the man-bear, then later Dumbledore, a kind but haggard old pedophile, and finally clutches on to Sirius Black, an old friend of his father's and Harry's godfather. Sirius has the curious ability to transform into a wild dog (i.e. he is an aggressive top). Harry's father had the ability to transform into a horse (a sly reference to penis size, lol horsecock). Harry himself has the ability to communicate with snakes (i.e. a deep understanding and appreciation of penises).
Harry is further traumatized when one of his classmates, Cedric, is also cruelly cut down by Lord AIDSmort. Harry attempts to warn the others that "Voldemort has returned" (i.e. AIDS is on the rise), but the majority of the wizarding community chooses not to believe this out of sheer denial. Only Dumbledore, the wise old one, and a few others believe Harry at first. Harry is at first ostracized but later vindicated for attempting to warn the community about the dangers of Lord AIDSmort. Sadly, Harry's newly adopted father, Sirius, is cut down in the process by one of Lord AIDSmort's henchmen (let's say syphilis).
Harry's career ambition after all this is to become an Auror - a dark wizard catcher (i.e. an AIDS awareness campaigner). This is the only way to ease the pain he feels from the loss of his dead friends and family while keeping other young wizards safe from the "dark side" of wizarding, i.e. AIDS.