Improvised Levelling
Level with stones, blocks under wheels, planks under wheels, makeshift levelling, field levelling
Improvised levelling means levelling a motorhome without proper ramps by placing stones, boards or other hard objects under the wheels.
It is common campsite slang, but not the recommended method: stones can split, slip or damage tyres. Purpose-made levelling ramps are safer, and the whole tyre should sit on the support.