Bubacxo (Pronounced Boo-Baa-Choh), is the easier-to-type version of the Esperanto word 'Bubaĉo', which means both 'Pickle' & 'Very Naughty Boy'. A double entendre if ever I heard one.
Plus, having the real-life nickname of Pickle doesn't hurt too much.
Disclaimer: Just because the Username is in Esperanto, please don't start talking to me in Esperanto. It's a passing hobby. I check in on it every decade or so. Probably won't finish learning it since it keeps changing & i'm too lazy.