It is usually used as an exclamation.
Vootie originated in 1955 in a
Mad Magazine parody where Dave Garroway's chimp (J. Fred Muggs - who also painted a cover for Mad) takes over the show. Instead of Dave's signoff, "Peace", the
monkey said "Vootie". It was later used in 1996 as an exclamation in
Star Control 3 by a race called the Xchagger.