From Teflpedia

The mouth /maʊθ/ is an organ at the head of an animal through which food is ingested. In the case of humans, it’s also important organ in vocal sounds, particularly speech sounds, and is also used for facial expressions in non-verbal communication, such as smiling.

EFL learners who struggle with dental fricatives and who have th-alveolarisation say /maʊs/ which is a homophone with mouse.