Xenochrony is executed by extracting a guitar solo or other musical part from its original context and placing it into a completely different song, to create an unexpected but pleasing effect.
One of the most prominent examples of xenochrony can be found on Zappa's rock opera Joe's Garage (1979), on which the guitar solos are all xenochronous (with the exceptions of "Watermelon in Easter Hay" and "Crew Slut").
The drummer was instructed to play along with this one particular thing in a certain time signature, eleven-four, and that drum set part was extracted like a little piece of DNA from that master tape and put over here into this little cubicle.
And then the bass part, which was designed to play along with another song at another speed, another rate in another time signature, four-four, that was removed from that master tape and put over here, and then the two were sandwiched together.
[1]Xenochrony can be heard as early in Zappa's career as 1968: on The Mothers of Invention's We're Only in It for the Money, the rhythm track from the chorus line of "How Could I Be Such A Fool" on Freak Out!