Paprika Garlic Aioli
After you have added about 1/3 cup of the oil, the risk of the mayo breaking is less and you can start adding a bit more (say, a tablepoon) at a time. Add at least 1 1/2 cups of the oil and any more you need to obtain the consistency you want. If it gets too thick before you have finished adding the oil, you can add a tablespoon of water to thin it a bit. Then continue adding oil.