Imparting electrical functionalities onto curved surfaces is an area of research which has been gaining momentum recently as such structures can provide multi-purpose parts enabling their use as cuff electrodes in tissue engineering for electrical stimulation and recording or as printed circuit AM parts for 3D antennas. Transfer printing using an advanced stamp design and a laser assisted metal deposition approach have previously been used for metallic deposition on curved substrates. However, both techniques were shown to be effective on the convex side of the structures with little information on the challenges of pattering concave structures. Here, we present compliant and conformal flexible stencils (100 micron thickness) to perform metallic deposition on 3D polymeric concave surfaces. Fused deposition modelling (FDM) and melt electrowriting (MEW) are used to manufacture fast prototype structures inspired by cuff electrodes that have a variable side opening depending on the design. The thickness and conductivity of the deposited metal is influenced by the incidence angle of the sputtered atoms and the shadowing effect. Successful deposition of 90 nm thickness is demonstrated on concave surfaces and the resistance is measured ~90 Ω. This approach provides a simple way to pattern electrodes on 3D printed concave polymeric structures.