Our two male chins, Dexter and Skillet, have always had very different personalities but usually have gotten along for the year and a half that they've been together. Over the last few weeks, however, things have not been quite the same. Instead of wrestling and chasing each other, now the chins don't really play together but run around independently. This isn't a huge problem (though it is sad to see them not having fun together), but what happens a few times a week is this: Skillet gets playful and tries to chase Dexter around. Dexter usually isn't having any of it and ends up in a corner. Skillet will sometimes get up in his face and Dexter will rear up defensively, start barking, and jutting his head out at Skillet. Sometimes Skillet will follow suit. In either case, a stern "No" usually stops them.
This happened last night. This morning when I opened up the cage, they were sleeping in separate igloos (not totally unusual, though typically they do sleep together). Skillet came down to wake Dexter up for playtime, but instead of just sticking his head in like usual, he started tossing bedding backward away from the igloo with his feet and doing that aggressive head-jutting thing into the igloo and I could hear one of them barking. I had to give them a "no" again and neither ended up wanting to come out for playtime.
Many times when Dexter is cornered and they almost fight, I'll notice fur coming out from his coat, usually around his back or hindquarters. Obviously he gets very upset, and I'm thinking that maybe when they were playing at some point Skillet got too rough and scared Dexter, which is why he refuses to play with him. Skillet, on the other had, will swish his tail (seems like in frustration) when Dexter won't play, and sometimes will make little distress noises (like barks but much quieter) to try and get his attention, or so it seems.
This gets really upsetting for me, and I worry that they might really end up fighting and injuring each other, which would mean being separated for life. Does anyone have experience with this or any advice on how to get them back to acting like best-buds during playtime again?