My male Maltese was neutered at 6 months and he never marked prior to that. But for some reason around 8 months when we were over at a relative's house, he started marking like a fiend. He's about 1 year and 3 months now and he still marks on occasion. Ever since we introduced our Yorkie he's been marking a ton around the house which is unusual for him since he'd never done it in the house before. But in a word, neutering doesn't always keep males from marking. I use a belly band when we are at other people's houses to keep him from actually getting pee everywhere.. for us it's more a pee catcher than a training tool. I've heard that the way to train w/ belly bands is that the dog will be uncomfortable being wet so will train to not pee in those areas, but personally I haven't seen that deter Tuffy.. he'll walk around in a wet belly band all day and not give a care.
