1. On both sides of each sausage, make a few slits using a small paring knife.
2. Rub mustard on each sausage.
3. Leave sausages to marinate until ready to grill.
4. Grill sausages on a coal or electric barbecue for about 10 to 15 minutes, turning them frequently with a fork, until brown and crisp.
5. Serve the sausages hot in rolls with pickles if you like.