How to use a Tourniquet

The bulk of injectors coming into NSP are either using tourniquets, or have got to the stage where they’re groin injecting because they say they ‘have no veins left’. But from my experience most people lack basic knowledge on how to correctly use a tourniquet.
Information about what makes a good tourniquet and how to use it can give really effective fast results for injectors and help prevent the progression to higher risk sites like the groin.