What would be Russian slang equivalent of "This song slaps!" in the sense that it's excellent, really cool, fire?
The word "slap" for us native English speakers brings to mind the flat of the hand hitting something with force, but it can refer to any loose object striking something. The implication in "this song slaps", I would guess, is one of "slapping someone in the face from out of nowhere", which immediately captures your attention and produces an adrenaline rush. But its true etymology may be different.