You do your best to put the dog into a secure room before you open the front door, but sometimes this just isn't practical. For example, there's the time the delivery man went away in the time you took to make the dog safe - meaning you had an unwanted trip to the depot to collect your parcel.
A friend suggested the answer is to teach the dog to sit on a mat on command. That way he sits still and you know where he is when you answer the door. Sounds a good idea, but how to put theory into practice?
To do this requires little by way of equipment but a lot by way of patience and consistency.
As well as time and patience you'll need: