Kick them out of your bed. That’s how you do that. They are animals. You are a human. Just kick them out of your bed.
Most people with the heart capacity to own dogs do not have it in them to kick a comfortable, sleeping animal out of bed. They roll their eyes and sigh and silently plead with you not to do it. I spend most night with no blankets at all because I don’t want to disturb one of my sleeping angels. That and they’re too goddamn heavy to shove around. And as soon as you fall asleep they usually creep right back in. So resistance is mostly futile.