1. Find a safe place to pull over.
2. Spot a few landmarks, road names etc
3. Call the venue and explain where you think you are.
4. Work with them to describe your location further if they are unable to work out where you are.
5. Listen to directions seeing if any locations are familiar, or can be related to your map or sat nav. Clarify with questions if needed.
Don't
1. Still be driving around so that any point of reference quickly becomes irrelevant.
2. Get your son to phone up, then put it on speaker phone.
3. Keep shouting visible road signs and locations at the person trying to help you, rather than answering their questions.
4. Hang up halfway through the call.
I almost hope he can't find us. But that's a bit harsh on the kids I could hear in the background!