As good as if not better than sex
"Have u tasted baileys ice cream? Its absolutely flaptastic"
by MsAcV September 27, 2007
Awesome, Amazing, fantastic, or excellent only better than awesome, amazing, fantastic, or excellent. Flaptastic is the word you use when there is no way to describe the awesomeness.
Wow, that cheeseburger was flaptastic, don't you agree, grandpa?
by FlapsRAwesomw August 11, 2014