I just got two male rescues, approx 8 months old. Skittles is small and fiesty, extremely inquisitive, and hard to keep still. Kit, who is dominant, is bigger, lazy and a little more inclined to sit still for a petting. They get along rather well in their cage, with an occasional dominance grooming and peeps coming over the evenings but nothing major.
Well now that they are starting to get more comfortable with out time, Skittles has no problems running around and exploring the whole area, hopping and weaving his way through the play pen. Kit really takes his time on the ramp down (it's rather large) and can spend an easy 20-30 minutes sniffing around before he feels comfortable climbing out. Well, I think he might be trying to encourage Kit out of the cage (DCN), but Skittles has this pesky habit of running around and back up to Kit to try and rush him out. Everytime this happens, Kit backs into the cage and will have none of it lol! I think Skittles is starting to feel like the play pen is his zone because while Kit takes his time figuring things out and cautiously exploring, Skittles will run in and out of range poking, prodding, and trying to *cough* emmasculate Kit. He'll get knocked back a couple of times, but Skittles just keeps coming back for more! The last two nights Kit had enough and squared up and they boxed pretty good. No damage but Skittles got knocked over and realized that the fight wasn't going to end well.
I broke it up, and for the rest of the night Skittles leaves Kit alone. It really looks like Skittles just wants to play, but the mounting makes me think he's trying to establish dominance outside of the cage. I wonder if Skittles will cow Kit into giving up his role (seems unlikely based on size and demeanor).
tl;dr - Kit and Skittles fighting over play time, seems like a clash in personalities, nothing too serious.