I've occasionally placed two of my snakes together for a quick photo shot. These are snakes, though, that have both passed through a quarantine time, are healthy, etc. and it's for only a few moments and under supervision. The only other time our snakes are together is adults for breeding purposes.

Housing ball pythons together isn't generally recommended for a variety of reasons, some of them being - possible domination by one snake on the other for available resources, risk of cannabalism, inability to determine which snake is sick if you see evidence of illness (loose feces, etc.), spread of disease, mites, etc.