Controlling the stacking order is a powerful way to engineer emergent properties in van der Waals materials. Parallel stacking of two layers of transition metal dichalcogenides, also known as the rhombohedral stacking order, can break the mirror symmetry between layers and generate an interfacial polarization that can be switched via in-plane sliding. Recently, we observed that large domains of interfacial polarization can exist in chemically synthesized rhombohedral MoS2 (3R-MoS2). Using a variety of spectroscopic and imaging techniques, we studied the polarization-induced interlayer potential and its switchability in few-layer 3R-MoS2. Interestingly, we found the domain size distribution follows a power-law distribution, suggesting that the shear strain occurring during the mechanical exfoliation can induce an avalanche of domain wall motion. Utilizing a graphene-3R-MoS2 heterostructure, we also demonstrated an efficient bulk photovoltaic device with high intrinsic speed.