Digital Interactive Maps on touch surfaces are a convenient alternative to physical raised-line maps for users with visual impairments. To compensate for the absence of passive tactile information, they provide vibrotactile and auditory feedback. However, this feedback is ambiguous when using multiple fingers since users may not identify which finger triggered it. To address this issue, we explored the use of bilateral feedback, i.e. collocated with each hand, for two-handed map exploration. We first introduced a design space of feedback for two-handed interaction combining two dimensions: spatial location (unilateral vs. bilateral feedback) and similarity (same vs. different feedback). We implemented four techniques resulting from our design space, using one or two smartwatches worn on the wrist (unilateral vs. bilateral feedback respectively). A first study with fifteen blindfolded participants showed that bilateral feedback outperformed unilateral feedback and that feedback similarity has little influence on exploration performance. Then we did a second study with twelve users with visual impairments, which confirmed the advantage of two-handed vs. one-handed exploration, and of bilateral vs. unilateral feedback. The results also bring to light the impact of feedback on exploration strategies.