Colloquial teen slang, originating from the eastern
seaboard of Australia, specifically
the New south wales
peninsula. to 'tell it' is to activaly participate in the chosen conversation/context.
example 1(conversation):
cuz1-"hey cuz, i got
roots last night"
cuz2-"
tell it!"
example 2(context):
cuz1-"hey cuz, theres a party in
ettalong tonight"
cuz2-"Should we tell it?"