Using a vegetable peeler, sharp paring knife, or a zester, peel a strip of orange peel from your orange. It doesn’t need to be too long – about 10cm is fine.
Try to get just the zest – avoid the white pith. My first attempt was so bad I ended up shaving the excess pith off with a knife, and then cutting the strip with scissors to get a nice neat edge.
Twist the zest over the drink to squeeze a few drops of orange oil in, and rub it around the rim of the glass.
For a large twist, simply wind the twist around your finger. For a tighter spiral, wind it around a skewer and pull tightly, without breaking.
Then simply place on the side of your glass.