Northern Radar, early 70's. Controller trying to identify a free calling Jet Provost student:
Northern: J25, what's your position?
Student: 2 miles south of Little Tenby.
Northern: I don't know where Little Tenby is. Can you give me another position?
Student: Um, er... 5 miles east of Churchford.
Northern: I don't know where Churchford is. Can you give me another position please?
Student: Er, um....about 6 miles south west of Steeple Down.
Northern: I'm sorry, but I don't know where Steeple Down is. Can you give me your position relative to Middleton St George?
Student: I don't know where Middleton St George is.
Canberra pilot listening patiently: Half time score - Jet Provost 3, Northern Radar 1.
As others have said, use a position that's likely to be known to ATC.