JARVIS kept trying to explain things to Dummy but it didn't always work. After Tony was kidnapped, Dummy eventually just stopped working.
Steve would come down to the lab and hang out and draw. Steve really got along with Dummy, and I think either taught him how to shake hands or high five. One time Steve spilled all of his colored pencils and Dummy started to pick them up one by one. Tony bought Steve a bunch of colored pencils from a school, because Steve wanted a specific shade of blue (it matches Tony's Arc Reactor) Dummy also made a smoothie for Steve, and Tony tackled him because he didn't know what was in it.