Incredibly good,
delicious,
fantastic, etc. It’s so good it almost feels unreal, like you have
the feeling of having your face being slapped. Alternatively, it is so good you kind of want to slap someone because it makes you so energetic and excited.
h: wat ya sayin
about that falafel wrap, mate?
t: ya, truly slapping faces!!!
massively.
h: I knew this place would hit.
a: What did you think of the film?
b: It wasn't really slapping faces, was it?
a: Yeah, pretty sub-par
if you ask me