1
general::
Also, lie down on the job. Be remiss or lazy. For example, They fired Max because he was always lying down on the job. This expression alludes to lying down in the sense of "resting." [Early 1900s]
American Heritage Idioms
2
general::
Phrase(s): lie down
to recline. • Why don’t you lie down for a while? • I need to lie down and have a little snooze.
McGrawhill's American Idioms And Phrasal Verbs