Backtagging: Yes
Threadhopping: Sure
Fourthwalling: Yep
Offensive subjects (elaborate): I generally have a stomach of steel when it comes to not being grossed out by things, but I draw the line at mentions of animal abuse/cruelty.

[IC]
Physical contact: You can try
Flirting with this character: Always
Fighting with this character: Go for it
Injuring this character (include limits and severity): Anything minor is always okay without asking first
Killing this character: Plot first
Using telepathy/mind reading abilities on this character: Sure