If your pup is not having fun, don't let the play continue. It should be fairly obvious to tell whether your dog is enjoying himself (he probably isn't)...is his tail tucked? is he trying to get away from the bigger dog? Your small breed could get seriously injured, and it could make him scared of large dogs in the long run. The labradoodle is not playing politely, and you as the owner need to protect your dog by not letting scary things happen to him. My experience from working at multiple dog daycares, is that large doodle mixes tend play very rough, charging at other dogs necks and barking/biting, then running away. It's incredibly annoying and hard play to manage, as it makes most dogs mad. The dog very well may be "playing," but think about how scary that would be for a dog so much smaller. I would never allow my small breed dog (or any size for that matter) to be pinned by the neck. You don't have to put up with that to become friends with your neighbor...try suggesting a walk with both dogs leashed and under control instead.