The speaker was talking about someone ad libbing or talking off the cuff. It is a word blend of “spitballing” (suggesting ideas, brainstorming), and “freewheeling” (uncontrolled). “Freestyling” (improvising) may also be in the mix, given the context. It is acknowledged that “freeballing” is indeed a word, meaning to not wear underwear, but in the context of the discussion, it is clear the speaker was mixing idioms. A big thanks to Mike and Anthony Kovacs (and Sandor?) for spotting the malaphor immediately.