A combination of the words fantastic and banter. To be used for the times the banter on its own is not enough, and fantastic just doesn't make the grade in expressing your past, present or future excitement over a situation or thing.
"I reckon tonight's gonna be bantastic"
"That poker game was bantastic"
"James got some bantastic abuse as regards to his massive shovel hands"
"I thought it was bantastic, but roomey just couldn't hack the manter"