LOL! No, I don't think they make belly bands for people but that is a hilarious comment.
If he were mine, I would have taken him into the room and showed him the wet spot and said "SHAME on you." He would then know what he did was wrong. It would give him the opportunity to correct instead of ignoring the problem. Some people say that if you don't catch them in the act, it doesn't do any good to show them their mistake later. But our dogs are smart. They know.
Anyway, to prevent that happening in the future and to be 100% confident that he won't go in someone else's house, you get a belly band. They are a piece of fabric made to go around the dogs middle and if the dog lifts a leg, they wet themselves. Protects the furniture. Also serves as a reminder to naughty males.
You can order online. Not sure the best place to get them, so will leave that to others. But here's what they look like ....