Define Glug Glug Glug Meaning

Glug Glug Glug
The sound that fish make at the end of very insulting (to someone of my form) jokes:

Dad: What goes "Miaow! Glug glug glug!"?
Me: A catfish.
OR
My brother: What goes "Neigh! Glug glug glug!"
Dad: A seahorse! That was a good one!
By Denice