the term "running their fingers" refers to someone who likes to talk sh*t, but the only way they do this is via facebook or other social networking media, or via text message, or anything that uses finger power to communicate. it's said running their fingers instead of mouths because they never say any of this stuff to someone in person. & they never would, because they are too p*ssy.
jessica: *typing on facebook* "ok. u can bring it..lol i dont have a prob fightin wit u..i do have a prob fighting wit people who are 300 pounds more then me :) SEE UUUU !!!"
everyone else: "naw b*tch, we know you just running your fingers. you ain't gonna do sh*t!"
& when she "SEES UUUU" she says nothing & runs away.