Within the UK such instructions are not used by ATC.
It was used quite extensively by RAF ATC because I always wondered what they really intended a pilot to do. I don't recall reading any document that gave an explanation other than an FAA document. I also remember being asked by an RAF ATCO when joining a hold to "keep it tight" to which I responded due you want me to change the timing from 1 minute, the response "no, just keep it tight" displayed a total lack of understanding of a hold.