The story
Derived from a Czech word which roughly means "headache" or "hangover", the expression "lomcovák" (sometimes spelled incorrectly by non-Czech speakers as "lomcevak") originated from the Moravia region, now in eastern part of Czech Republic, famous for its Jelinek slivovitz, a traditional Czechoslovakian alcoholic drink, and is commonly used to describe the rotating motions of one who has had one too many. The English use originates from Czechoslovakian aerobatic pilot Ladislav Bezák's mechanic, who at a 1958 air show in Brno, Czechoslovakia, jokingly called Bezák's tumble maneuvres "lomcováks" when asked by journalists what they were.
Etymology from Wiktionary, CC BY-SA 4.0.