For users with visual impairments, who do not necessarily need the visual display of a mobile device, non-visual on-body interaction (e.g., Imaginary Interfaces) could provide accessible input in a mobile context. Such interaction provides the potential advantages of an always-available input surface, and increased tactile and proprioceptive feedback compared to a smooth touchscreen. To investigate preferences for and design of accessible on-body interaction, we conducted a study with 12 visually impaired participants. Participants evaluated five locations for on-body input and compared on-phone to on-hand interaction with one versus two hands. Our findings show that the least preferred areas were the face/neck and the forearm, while locations on the hands were considered to be more discreet and natural. The findings also suggest that participants may prioritize social acceptability over ease of use and physical comfort when assessing the feasibility of input at different locations of the body. Finally, tradeoffs were seen in preferences for touchscreen versus on-body input, with on-body input considered useful for contexts where one hand is busy (e.g., holding a cane or dog leash). We provide implications for the design of accessible on-body input.