Guard Dog

Just as a dog guards and protects his or her owner, the idea of this is that a person who initially feels obligated to protect someone that matters very much to them that could potentially be a relative, close friend, or partner.

" did you see when Eric hit Rey last week? Rey's friend was with him and attacked Eric like he was Rey's Guard Dog!"

Mouthbreather

a person who struggles/has difficulty breathing through their nose due to allergies or other illnesses or symptoms related

the top paragraph says everything you need to know about a mouthbreather