Quick background. I have two dogs, a 1yo Great Pyrenees neutered male, Cthullu, and a 6yo(est) Dachshund/Miniature Pincher intact male, Otto. Otto is going in for his vet check and to schedule his neuter on Tuesday. Here's the problem. When we first got Otto, he marked around the house. We couldn't afford to have him fixed at the time, and didn't know if we were keeping him or not. I know I should have just gotten him fixed straight off, but it just wasn't possible. So instead, after a lot of training, we managed to control his marking. I won't say he was 100%, but it was predictable, ie don't set the new piece of furniture at his level until it smells like our house, keep your shoes in the closet, and if you visit a house with other dogs, take your dirty clothes straight to the hamper. We still had a few accidents here and there, but they were few and far between. I was worried that he would start marking when we got the new dog, but he didn't. If fact, his accidents in the house completely went away. (He did pee directly on Cthullu the first time they were in the yard together, lol, but no marking inside) But about 2 weeks ago, I started finding spots in random places. The pillow on the couch, the middle of the living room, the side of the refrigerator... 3 days ago, someone peed in the middle of our bed. Because of the size difference of the urine stains, and the fact that Otto isn't neutered, I assumed that these little piddles were from Otto. So we went back to potty training 101, and for the past 3 days Otto has had constant supervision, or been locked up. And I scheduled his vet appointment to get his neuter done with. BUT, and here's the big but, last night, a few hours after I had put Otto away for the night, I got up to get a drink and stepped in urine. There was a dribble line in front of the TV in the middle of the living room carpet. I looked like Otto had done it, because of how small it was, but that's not possible. So it had to be Cthullu, only I can't figure out how such a big dog could piddle such a small amount. And, he's fixed. He's been fixed since we got him, and he doesn't even mark on walks. He's a one shot pee-er, where Otto is a pee on ever pole, tree, and fence kind of dog. But it has to be Cthullu. So, why would a neutered male suddenly decide to start marking in the house, how can such a big dog pee such small amounts, and other then the obvious of supervision and having Otto fixed, what can I do to stop this? I'm already planning on cleaning the carpets with nature's miracle as soon as I get my grandma's carpet cleaner again.