Introducing New Chins

[Hobbes]

Just found a second chin at local rescue.  He and my first chin have been getting used to each other over the past two weeks.  For the mostpart, they play nicely, but every now and then, the original chin gets a little "frisky," so to speak.  They are both males.  Can this behavior lead to an injury or do they have a built-in self-preservation, so that the friskiness will not lead to anything serious? 

[Debbie.nl.ca]

They are just working out who's boss. As long as there is no fighting and fur flying they are fine.
Normal