Behold what *might* be millipede sex.
As we were walking up Round Mountain, I noticed a millipede eating a small puffball. While I stopped to watch and try and photograph the event, another millipede sauntered up (not sure if millipedes saunter, but I digress) and started to feed as well. The two ended up touching at one point, and what you see here began to unfold.
My initial guess was that there was some sort of territoriality going on between the two, perhaps over the source of food. They loosely kept this embrace for five minutes or so, moving away from the fungi and down the log. Eventually, they decoupled and parted ways.
After returning home, and reading about millipede sex (which involves gonopods, modified legs around the 7th segment, two penises and transferring sperm packets) I think this was might have been what I was observing instead.