While this literally expands to "tah tah for now, okay, thanks, goodbye..." the pop culture connotation is that you are making a flippant or perhaps merely hasty retreat from a conversation with the
speed of a 1980s or 1990s
Anime school girl. The character of Yukio in
Deadpool 2 comes to mind, as well.
One can also shorten it further as "ttfn kthx bai" or "ttfnkthxbai".
Certainly related to, though a nuance in use of the constituant parts "ttfn" "kthx" and "bai". The "ttfn" adds a friendly aspect, while the "kthx" adds
snark, followed by the finality of "bai" - when combined it forms a powerful and ambiguous immediate ending to a conversation, though ironically is often not the last words. It'
s quite common to have the other
party respond with expressions of either offense or solidarity with your assertion using this phrasing.
Friend: "So yeah, I know I've been telling like every gory detail but ..."
doorbell rings
You: "OMG, my pizza is here! I've got to go, sorry!"
Friend: "No problem..."
You: "ttfn
kthx bai"
Friend: "
Bai"