Just get him neutered.
I have 2 boys and they have never humped anything, but one marks, even after being neutered. Not sure if these habits just depend on the boy. If he's a marker you can always put a belly band on when he's in the house. Boys are super super sweet, I just adore my boys! I can't imagine having a girl! LOL
__________________ “Petting, scratching, and cuddling a dog could be as soothing to the mind and heart as deep meditation and almost as good for the soul as prayer.” ― Dean Koontz |