The Dzyaloshinskii-Moriya interaction (DMI) plays a crucial role in the coexistence and strong coupling between ferroelectricity and incommensurate magnetism in perovskite multiferroics like RMnO3 (R = Gd, Tb, Dy). Using Monte-Carlo simulations and zero-temperature exact calculations, the authors study a model incorporating double-exchange, superexchange, Jahn-Teller, and DMI terms. The phase diagram shows a multiferroic phase between A and E antiferromagnetic phases, consistent with experiments. The DMI is essential for inducing ferroelectric lattice displacements and stabilizing helical magnetic structures. The DMI also contributes to the observed in-plane polarization in applied magnetic fields. The study shows that the DMI is responsible for the stabilization of the ICM-FE phase, which is a key feature of these materials. The results are in agreement with experimental observations and provide a microscopic mechanism for the magnetoelectric effect in incommensurate magnets. The DMI is found to be independent of the orbital structure and is related to the interaction between spins induced by symmetry-breaking ionic displacements. The study highlights the importance of the DMI in understanding the behavior of multiferroic materials and its potential relevance in other IC multiferroics.The Dzyaloshinskii-Moriya interaction (DMI) plays a crucial role in the coexistence and strong coupling between ferroelectricity and incommensurate magnetism in perovskite multiferroics like RMnO3 (R = Gd, Tb, Dy). Using Monte-Carlo simulations and zero-temperature exact calculations, the authors study a model incorporating double-exchange, superexchange, Jahn-Teller, and DMI terms. The phase diagram shows a multiferroic phase between A and E antiferromagnetic phases, consistent with experiments. The DMI is essential for inducing ferroelectric lattice displacements and stabilizing helical magnetic structures. The DMI also contributes to the observed in-plane polarization in applied magnetic fields. The study shows that the DMI is responsible for the stabilization of the ICM-FE phase, which is a key feature of these materials. The results are in agreement with experimental observations and provide a microscopic mechanism for the magnetoelectric effect in incommensurate magnets. The DMI is found to be independent of the orbital structure and is related to the interaction between spins induced by symmetry-breaking ionic displacements. The study highlights the importance of the DMI in understanding the behavior of multiferroic materials and its potential relevance in other IC multiferroics.