What happens in OM and the states that you get to can only be achieved with another person.
There are many reasons for this from the way the bodies intertwine, to the mechanics of the precise stroke we use for 13 minutes and then the other one we use for 2 minutes. But the more you learn about it, the more you see this is the case.
Think of it as backscratching. What feels better? Scratching your own back or relaxing and guiding someone until they hit the spot?