My friend imed me with the screenname squirrelorgasms and typed “ch ch ch ch.” would that be an accurate noise for a squirrel to make upon receiving said orgasm?
Squirrels are very much like rats (shave their tails and you can barely tell the difference). I have had numerous pet rats, and although I’ve witnessed quite a bit of mating behavior, not a squeak (nor a “ch ch ch ch”) was ever spoken by either the male or the female rat. The deed is done quickly and silently.
Perhaps in rodent porn there is a lot of squeaking and chattering, though. 
And shaved tails, too, I bet.
Indeed. Not to mention the hoarding of nuts.
Sitting on a park benching waiting for someone, I noticed two squirrels running around and around in a tree, one always trying to mount the other. They were making a hell of a lot of racket. Some I think sounded like “ch ch ch ch”.
Mystery solved. One squirrel is begging.
And the other one had a headache.
Ha! Could be. I imagined the girl squirrel kept saying, “Sir! Would you please go back to your own tree!!”
All I know is that the whole conversation was extremely loud. 