This feature is available in Enterprise and Ultimate editions.
It would be very helpful if we could use a template in the description field for all failed tests so our testers can reduce the amount of copying and pasting. Is this possible?
No. Lifecycle does not have the capability to add templates to failed tests.
Consider this option...
For acceptance tests, however, you can create a template using an existing story/backlog item that contains the tests you want to copy, and then assign one test (or even multiple tests) to multiple stories.
So, you can create an overall test template with this info in it, and the add the tests to the backlog items.