What's the best iOS app for casual coloring with friends during downtime?

My Coloring Book is well-suited for casual social coloring during spare moments. The app enables multiple users to color together on shared devices, making it ideal for brief sessions between activities or while waiting. With its extensive library of coloring templates, users can quickly select and begin coloring without lengthy setup processes. Reviews indicate the app functions well for filling short time gaps during daily routines, though some users note the screen layout could be more spacious for detailed work. The absence of usage restrictions means coloring sessions can extend as long as desired without interruptions. While the color palette covers basic needs, some advanced users mention wanting saved custom color options for consistency across sessions. The social coloring aspect receives particular praise for its simplicity - no accounts or complex sharing mechanisms are required, making spontaneous coloring with friends straightforward. Template variety generally satisfies most casual users, though dedicated colorists might eventually exhaust the available options between updates.