The title used in Spanish-speaking territories roughly translates to English as 'The Third Sex Having Fun.'
In an early draft of the script, the protagonists were Hollywood stuntmen.
This was the second film Kevin Coughlin had worked on with Brooke Bundy, the first one, filmed a year earlier; The Young Runaways (1968).
This was originally rated X but they trimmed it down. It also resembles a "Three's Company Episode"; or "Love American Style'.