Congratulations. I have an English Mastiff and there isn't a sweeter 175 pound dog anywhere. He was the runt as his granddaddy weighed 220. He guards his couch well by laying on it. It used to be my couch but I have to go to work.
He doesn't much care about deer but he sure dislikes coyotes. He likes to wait until he is up on them near the barn (I have barn cats that draw them) and then explodes in a loud freight train roaring charge. Ferocious, but not fast. Coyotes can fly. You never even see their legs moving.
As for your dog, if you are not going to breed him get him fixed. I say this for two reasons. As a house dog you really don't want his pecker popping out of its sheath all the time as he tries to hump the mother-in-law or the kids. Second, getting him fixed will keep him from roaming when other dogs are in heat and it will calm him down. Just wait until he is old enough to get past the puppy stage.
All dogs are social animals. The more you pay attention to them the better they will adjust. My dog waits on his dog bed until my wife gets up and then climbs on the bed to snuggle with me.
What a fine dog. I have owned shelties and basset hounds but from now on will always have a mastiff. They are fantastic with kids.
Please click on my screen name to see our furkids. We have an American Mastiff, bred by former OEM breeder Frederika Wagner. 7/8 OEM, 1/8 Anatolian Mastiff. I agree with you about the neutering, it was in our contract.
Tinker is one and a half in the photo, now just turned 3 yo. What a wonderful, wonderful dog... Grandkids love him, even the baby. He's actually kind, which is hard to believe until you see him lay down in front of the granddaughter so she can pet him...she grabs him by the collar, and he just walks with her at her pace.
We'll likely get another in a few years, another male, he's probably the smartest dog I've ever known. His boss, the minpin Bebe in the photo, is dumb as a stump, but they're best friends.
Our black Lab was two when we got him from a Lab rescue group.
He was fixed at that time, but, as you so elegantly put it, his "pecker keeps popping out of its sheath" to this day when he's excited or happy.
P.S. He's always excited and happy.