Most humans on Earth (and other beings on planets) know this gesture as giving someone a bump. You're bumpin' it. Bumpin' knucks.
Real news reports that Fox Noise Channel likes to call it "Terrorist Fist Jabs". Other lunatics like to call it "Hizbollah hand jabbing"
Anyway, the whole point to this is to check out RDV Animations new up-and-coming product "RDV Meet & Greet HUD 2.0" (which I hear is actually going to be released TODAY so visit Muse Isle. One dual-avatar animation option includes the awesome "bumpin' knucks."