Lederhosen literally translates to "leather breeches" and refers to the traditional Bavarian and Austrian leather shorts or trousers.
In this song, DJ Ötzi, a self-proclaimed "Mann für Amore" (man for love), proudly declares, "I bin a Held in Lederhosen" (I'm a hero in Lederhosen) and later, "Host du die Lederhosn aun" (You have your Lederhosen on). It's a fun, culturally specific word that immediately evokes the festive, folk-pop atmosphere of the song and the artist's persona.
DJ Ötzi sings this one in broad Tyrolean dialect, and the joke lives in the dialect. The narrator has decided he is irresistible and simply announces it: "I bin a Held in Lederhosen" ("I'm a hero in leather trousers"), "I bin der Anton aus den Bergen" ("I'm the Anton from the mountains") — a wink back at "Anton aus Tirol", the 1999 hit that made his name. His self-portrait is "A Körper wie a Baum und a Hüftn wie a Traum" ("a body like a tree and hips like a dream"), and he offers it to his partner as though it settled the matter.
The chorus is the whole argument: "I bin wia i bin, I taunz und i sing, I moch heut mei Ding" ("I am how I am, I dance and I sing, today I do my own thing"). The second verse punctures the boast. He comes home in the evening — "Doch komm ich obends zu dir haom" — and finds "Host du die Lederhosn aun" ("you've got the Lederhosen on"): she is wearing the costume he built his legend out of. He kisses her on both cheeks, "A Bussal rechts, a Bussal links" ("a kiss on the right, a kiss on the left"), and carries on singing anyway.