hmhmmm okay I guess it is linked with the experience you have playing the game... but no, no skill is required (when I do it at least).
And yes, I use that cheap technique sometimes as well because I'm a victim of it most of the time xD.
When I do, I just throw the nade up front, no cooking, right where [I KNOW] enemies are. I consider this move to be ridiculously repetitive and unrealistic.
add 3xgrenades perk + larger explosive effects, and you get collateral damage xD