I'm sure there a few of these posted, but I'm not sure what the terms are: Our lab will often lay down when seeing other dogs, which is fine, and better than any aggression for sure. He'll either wait or stand slowly and stalk a little. Then its either sniff, chase or sniff and see-ya. In the last 2 weeks he's had 3 rushes at dogs on leads: 1) Mix-breed about his size, on muzzle. Ours layed-down off a path and I walked on (usually a good way to get him to break and follow). This time he darted out and chased the dog aggressively around the owner. Got him away in 10 secs or so. Abuse, apologies, soul-searching. No previous incidents I can think off with a similar dog. Only thing I can think of is 10 mins before this in an open space, a larger dog was eyeballing and bullying him about (I had to step in to move it at one point as it was too much for play) 2) On the same open space, a Schnauser came on, and there was a little eyeballing from the Schnauser. Ours was playing with a whippet and a Daschund - the Dashcund had a growl at the Schnauser and then ours did the same as above. Talked to the owner a bit after, the dogs were fine and we swapped rewards for them. Both young dogs, both done it before. Ours has had some horrid Schnauser interactions before. 3) Border terrier - ours off-leash, laid down, then rushed. Madness ensues as the owner decides best course of action is to swing the dog around in the by its leash while ours chases. I intervene, catch terrier mid-carousel-flight, and then ours. Met that owner on he other side of the park (we both left the initial as it wasn't calm and a busybody got involved making things worse). Turns out the terrier was one that had needed to be leashed near our dog a few times before as it is aggressive and has behavioural problems (3 occasions with our dog, just struts up and starts having a pop). A different border had also attacked ours when he was doing his laying down greeting as a pup. maybe related, maybe he just recognised this dog. I'm worried there may be a bit of bully in ours due to the others being on leash, but I'm also aware that he meets A LOT of terribly socialised dogs and owners. The parks are full of them, plus dogs in-season running everywhere (ask why they aren't on a lead, get called a misogynist. (That's the world today apparently)) - its a nightmare! In the last week, he's also be rushed by other labs, (ours on and off-leash) so he may be getting more anxious each time? I don't think his testicles are wholly to blame as is often suggested! Has anyone else had the lay-down greeting turn into this? Any thoughts generally would be great, happy to answer any clarifications. I've decided to try and stop on-leash meetings of new dogs, as these are often in pathways where eyeballing dogs might pen him in - he'll (rightly) react a little then. I'll also need to stand with him when he lays down (i think?), but I'm trying to figure out whether it is heightened when other dogs are leashed, just certain dogs he remembers, or god knows what else.