He hasn't got one in mythology, merely titles and epithets.
Poseidon was known as the "Earth Shaker."
the function of Poseidons temple was for Poseidons honor.
Rhea.
cronus
Neptune
Cronus and Rhea
Triton
Rhea.
a trident
He doesn't had friends
Give it back to Poseidon.
In myths, he does not have one.
you don't