when "rappers" are flinging their hand back and forth while freestyling, are they emulating...

[BlahBlahYouToo]

a) mixer/turntables
b) metronome to help them keep their rhythm
c) uncontrollable muscular spasms

 

[Dumac]

Video? I've never seen rappers do this IRL, so I don't know exactly what you are talking about.

 

[KeithTalent]

Did you say rappers or fappers?

KT

 

[scott916]

A mixer, seems pretty obvious to me. Fikky fikky!

 

[SlitheryDee]

They're petting imaginary piles of drugs, money, and women with no self respect.