male boxer pees on family beds

Question
Hello Nicole
I would like to inquire about my male boxer Buddy that has just turned 9 months.  He has been quite clean, not peeing in the house.  His training went relatively well and he was peeing outside at an early age.
He has been castrated (5 months of age).  Prior to his castration he peed on our living room couch (no one witnessed this and we were told that it was probably a domination issue which would be resolved post castration).  Recently he has peed on both my daughter's and son's bedspreads.    My daughter had friends over and ran to her room to pick something up--Buddy ran after her and entered her room, jumped on her bed and peed.  
Just recently Buddy peed on my son's bed.  My son was away for a total of 10 days on vacation with friends leaving his bedroom door closed.  When my son returned from vacation Buddy followed my son to his bedroom where he jumped onto the bed and peed.
Buddy is allowed to venture upstairs onto the second floor where we have our bedrooms but the doors remain closed.  He can enter the room only with supervision.
Buddy has also an issue with aggression (my husband says that it is not aggression that it is play).  Buddy gets "aggressive" whenever someone has shoes on in the house or especially when we are in the backyard where Buddy plays and pees.  He comes at you jumping sometimes crouching and "growling" he never shows his teeth and honestly does not look like he is mad (his ears are not back and his tail remains up).  He seems to want to play and although we do not give him attention at times like this playing with him does stop this behavior.  My husband is unable to pick up Buddy's excrements or even go into his outside play area without Buddy jumping on him, bitting his shoes and latching on making movements impossible.  I have tried on one occasion to catch Buddy during an outside moment such as this, pin him to the ground and hold his neck down in a submissive position.  This stopped him for around 10 minutes but has not worked since.  Buddy is okay around the fenced pool where he lies down (most of the time he tries to lie down wherever he thinks you will sit) on a lawn chair.  
Everyone loves Buddy but as he grows and gets bigger I worry more and more about this behavior.  
We are a family of 5 with each parent working.  There is for the most part someone home during the day as the 3 kids have variable school schedules.  Buddy has taken a training course with my husband and son.  He learnt how to heel with a leash (he still tries to pull intermittently on the leash especially when he sees another dog or sometimes other people and bicycles)
I am hoping that you will be able to help with our two problems (peeing on beds, aggressive play)
Thank you very much for taking the time to read this
Hoping to hear from you
Christine

Answer
Buddy is at the age where he's testing his boundaries; it is your job to be sure that he knows what those boundaries are, and enforce them.  There are several things going on here, but the underlying issue is just that you need to continue his training and teach him what is and is not acceptable behavior.  You can do this in several 5-minute sessions during the day - all members of the household who are mentally and physically able should be involved in the care and training of the dog.

Forget about the "pinning him down" thing.  This only increases the conflict between you and him, which just creates mistrust and can set back any relationship-building you might have done.  Remember that he's like a toddler - he's curious, he's active, and he doesn't know right from wrong.  Boxers in general are independent and creative thinkers, and tend to do far better with positive-based training than they do with compulsion-based training.  ("Clicker training" is the most common example of positive-based training.)  Set him up to succeed, reward behavior you want, ignore behavior you don't, and above all be fair and consistent.

The urination is probably part of this adolescence thing, and a reaction to the changes in his routine, but if it continues a medical workup is in order to be sure there are no underlying physical causes.  Since he's peeing when he's on your furniture, teach him that he's only allowed up on the furniture when he's been invited.  As for the jumping up, figure out what you want him to do instead, and teach him that.  ("Sit" is a common alternate, contradictory behavior - he can't sit and jump up on you at the same time.)  Teaching him to jump up on cue will also teach him that there's no payoff for jumping without the cue.  You note that playing with him will stop the behavior - which means that he's been rewarded for jumping up on you, and so it will be harder to change his behavior (but it is certainly possible!).  As far as cleaning the yard goes, put him in his crate or at least in the house when you want to clean the yard, until you get the jumping stopped.  You may need to set up your yard so that there's a "time out" area - somewhere you can go, that Buddy can't, when he's jumping on you and won't stop; he will soon learn that jumping up means you go away (removal of attention - even if you're not deliberately giving it - is a Bad Thing for Dogs), and keeping four feet on the ground (or sitting, or bringing you a toy, or whatever) means you pet or praise or treat or play with him (Good Things for Dogs).

Some good sites for you to visit, with many articles on addressing these and other common behavioral issues, are:

http://www.clickersolutions.com/articles/
http://www.shirleychong.com/keepers/
http://www.clickertraining.com/node/834
http://www.clickertraining.biz/

Also, you might be interested in these books:
"Bones Would Rain From the Sky" by Suzanne Clothier
"The Other End of the Leash" by Patricia McConnell
"The Culture Clash" by Jeanne Donaldson
"Family-Friendly Dog Training" by Patricia McConnell
"The Power of Positive Dog Training" by Pat Miller

Good luck - I feel sure that with time and training, Buddy will be a fantastic canine companion for you!