My old dog has a female sparing partner for about 5 years now. Greatest thing to see is them going at it with the friendly wrestling. She turned a bit grumpy the last couple of years tho. The young dog i have ( 3 year old ) is hell but never touched the old dog while in his presence ( grabbed his dam a couple of times tho ). I think he sees him as surogate father since he's been around him since he was a pup. The old lad also just ignores him most of the time like he knows that young buck aint nothing but trouble !