help me get knotted

It's been a while I have this fantasy about finding another zoophilie and being friend with it in person and that he could help me get knotted and maybe let me touch a horse cock too but after all I've seen it's like all posts other then the one about trying to find people or couple in another...

First of all sorry for my bad English I have two half German shepherds, and I usually have sex with them (I receive), but I keep the knot out because it scares me. The size and length they can get , it's safe to take them all? I don't want to get hurt or hurt them. And I don't know how much...