I gotta be honest, I'm more of a high-fiver. I find fisting only works with certain people. Like, old people don't get fisting at all. Slightly younger people sort of like fisting, but they prefer a solid handshake. Then there's this grey area, fisting-crowd generation, mixed in with the high-fivers. As for the youths, I don't know how much fisting they do. I assume they don't think it's cool anymore and have moved onto something more complicated.
I don't really fist with anyone. I don't fist my mom or my grandmother (though I think she'd be into it), and I don't fist with my brother. I'll do the devil horns sometimes, if the situation is appropriate. I guess I'm more of a two-finger guy all-in-all. Though sometimes I will throw my thumb in there.