so I have a 10 month old GSD (female) and a 5 month old Olde Victorian Bulldogge (male). They are relatively fine off leash except for 2 issues:
They play fight hardcore. My little OVB can get way too rough though and starts biting my GSD's neck and shaking while growling and my GSD clearly does not want any part of that (this also causes her to become more aggressive).
The real issue though is my GSD will role my OVB over and then clamp down on his neck to the point where he literally starts to gasp because he can't breathe. She will not stop unless I break them up. It is the scariest sound in the world because she is literally cutting off his breathing (yes I know he can still breathe a tiny bit or he wouldn't be able to make the gasping sound)I have found no help on the internet because most search results come up with choke chain issues.