All of these
definitions are wrong, or half there.
A dick rider is a person who is usually and overzealous mindless fan of anyone(be it a rapper, singer, athlete, music genre, band, or any given thing). A dick rider see's no flaw in whatever they are dick riding at the time, and if you happen to offer an opinion or simply not like whatever a dick rider likes, the dick rider will consider your a "hater" for offering your opinion.
Most of the times
dick riders are female fans of a band, rapper, or singer who constantly praises the graces of a music artist they never met, or are going to touch in that star's fame . Male
dick riders are usually men who want to be or picks up the "swag" and attitude of their favorite artist, and they'll swear that's how they are(this is usually a phenomenon in the hip-hop culture)
Steve -"Jamal knows all
the words to every Lil Wayne song, owns all his albums, and even models his
personality after him, and he get's upset when you say Lil Wayne isn't
the greatest"
David - "Jamal is such a Dick Rider