My GSD is about to turn 9 months old and is still intact... He has started trying to mount one of our neutered males(different breed and they have always gotten along very well), they are also a bit over a year apart in age. I don't want this to escalate anything so should I be stopping this behavior, should I be correcting for it? So far he hasn't shown any aggression that I noticed, before he tried mounting today he was first trying to initiate play. I was going to wait until he was a little bit older to neuter but is this a sign I should do it sooner? My breeder didn't want me to do it before he turned 18 months. I've just never had an issue like this with my other dogs so I'm not quite sure how to handle it. Any advise would be appreciated!