first knot

A freind of mine just got a male German Shepard dog from family who no longer can care for him. :( BUT! He's not fixed l, and she's very into beast stuff. But she's never had the chance to do it irl yet. She has plenty of toys and stuff but never the real cock. This dog is about 5, and he's...

So I have a Male GSD still intact and I REALLY want him to mount me. He's 21 months old so 2 years in october. Would it be safe for him to and would it cause a change in behavior as I dont want him to try anything with anyone else in the house. I do still need to have his hips looked at as his...