Idioms and Phrases with have oneself
Enjoy something, as in Be sure to have yourself a good nap, or They were having themselves a great time at the fair. The oneself in this colloquial expression adds emphasis to the verb have.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.