This song has its own en.wikipedia.org page:

“Smells Like Teen Spirit” was one of several songs written following Nirvana’s first recording sessions with producer Butch Vig in 1990. Singer and guitarist Kurt Cobain began writing it a few weeks before recording their second album, Nevermind, in 1991.[4] He said it was an attempt to write a song in the style of the Pixies, a band he admired:

I was trying to write the ultimate pop song. I was basically trying to rip off the Pixies. I have to admit it. When I heard the Pixies for the first time, I connected with that band so heavily that I should have been in that band—or at least a Pixies cover band. We used their sense of dynamics, being soft and quiet and then loud and hard.[5]

When Cobain presented the song to his bandmates, it comprised just the main guitar riff and the chorus vocal melody.[6][7] Cobain said the riff was “clichéd”, similar to a riff by Boston or the Richard Berry song “Louie Louie”.[5] Bassist Krist Novoselic dismissed it as “ridiculous”; in response, Cobain made the band play it for an hour and a half.[5] Eventually, Novoselic began playing it more slowly, inspiring drummer Dave Grohl to create the drum beat,[8] which drew from disco artists like The Gap Band.[9] As a result, it is the only song on Nevermind to credit all three band members as writers.[10]

The title derives from a phrase written on Cobain’s wall by his friend Kathleen Hanna, singer of the riot grrrl band Bikini Kill: “Kurt smells like Teen Spirit”.[11][12] Hanna meant that Cobain smelled like the deodorant Teen Spirit, which she and Tobi Vail, his then-girlfriend, had discovered during a trip to the grocery store.[13] Cobain said he was unaware of the deodorant until months after the single was released, and had interpreted it as a revolutionary slogan, as they had been discussing anarchism and punk rock.[14]

So Dave has just always been into disco, he just knew what paid the bills.