It is used to refer to a new age Hip Hip subculture, usually around Trap music.
It is believed that the name was coined because of the heavy use of ad libs such as ‘skrr skrr’ (the sound of stretching tyres) in the music.
I think I'm dating a skrr skrr nigga 💀.
Please send help 😭💔
— Tshepii 🌻 (@tshepiichuene) February 2, 2019