Green’s Dictionary of Slang

(US campus) performing instinctively (and successfully).

1997		D.F. Wallace ‘Tennis Player Michael Joyce’s Professional Artistry [etc.]’ in A Supposedly Fun Thing I’ll Never Do Again 217: [footnote] Serious tennis is full of [...] multisemiotic terms—’love,’ ‘hold’ and ‘break,’ ‘fault,’ ‘let’ as a noun, ‘heat,’ ‘moon,’ ‘spank,’ ‘coming in,’ ‘playing unconscious,’ and so on.
2024		D. Rucker Life’s Too Short 110: ]O]nce I heat up, I become unconscious. We mop up the court with these kids.