Everyone has their own workflow for texting oddly shaped objects in 3D. Certainly UV mapping will play a large role in how successful or easy the texture mapping process will be.
The focus will be on the mapping process, not the material
Here, CyBear shows us 3 different methods that can be used for texture mapping one such irregular-shaped object, the dreaded Banana. Probably the easiest, but not the most effective way, is to simply use a series of planar projections to place the textures where they are needed on the Banana.
CyBear also shows how using Cinema 4D’s powerful Vertex Mapping feature can allow you more control over the placement and creation of the texture mapping.
Finally, the last method uses C4D’s BodyPaint for texture mapping the banana.