All you need is denatured alcohol. If you look in your Audi owner's manual it might even recommend this as part of the routine paint washing and care instructions.
Pour some denatured alcohol on a soft microfiber towel. Place the towel on the spot of sap and let it dwell for about 15 seconds. You'll then be able to wipe it away effortlessly. If you are gentle enough it will not mar the finish and you will be left with zero residue. This works on fresh sap as well as dried, baked on sap. Also, if the sap is from a pine tree sometimes turpentine works a little better; however, in my experience denatured alcohol works the best in almost any situation regardless of the type of sap involved.
If there is a stain in the paint after you wipe away the glob of sap it will usually go away within a few days as the organic material degrades from UV exposure. If the stain doesn't go away the sap might have fractured the binder/resin linkages in the clear coat... this is not repairable and usually only happens if the sap has been stuck on the paint for several weeks or months. If the paint is fractured you can see it under a magnifying glass or microscope it will look like the paint is cracking apart.
