It is bedtime. Your dog is stretched across your pillow, and when you reach for their collar they growl. Stop reaching. A growl is a warning that this moment is hard for them, not an invitation to prove who is in charge. Give space and do not physically drag or lift them off.
If safe, invite them to move with a familiar cue or toss a treat to a clear area away from the bed. Do not approach if they stay tense. For now, prevent access to the bed when nobody is supervising and offer a comfortable place of their own. Keep children out of this situation. If the dog has bitten or is guarding the room, use barriers and get qualified behavior help. A new growl or sensitivity to touch should be checked by a veterinarian, pain can change how a dog responds to moving.
Practice when there is no conflict
Teach an "off" cue on low-stakes furniture where your dog is relaxed, rewarding them for stepping down voluntarily. Sometimes invite them back, so moving does not always end comfort. Reward going to their own bed. If the real bed remains contentious, skip rehearsing there until a professional has helped you set up a safe plan.
You do not need to let your dog sleep on your bed. You also do not need to win a nighttime confrontation. Good management means nobody has to lean over a worried dog to reclaim the pillow. For more on guarding a resting place, see the resource-guarding guide, prevent another confrontation and get qualified help if anyone could be bitten
Sources: Dogs Trust: Resource guarding in dogs. Dogs Trust: How to keep your dog off furniture.