As I look up the dictionary, it says that 'to get off' means 1. to start off / to leave for somewhere 2. to stop something 3. to escape
But I don't understand the meaning of 'to get off opinions'. Does that mean like, making opinions? Here is the example, which is from 'Baker's blue-jay yarn' by Mark Twain.
He couldn't seem to make it out, so he raised a yell, and three more jays come. They all examined the hole, they all made the sufferer tell it over again, then they all discussed it, and got off as many leather-headed opinions about it as an average crowd of humans could have done.