Many people have public bathroom anxiety and fear pooping in public toilets because of the sound or smell which makes it embarrassing for some people.
However just remember that everyone poops and pees and poop smells for everyone.
However if you're needing to poop then you could flush the toilet a few times to mask the sound of pooping and avoid making grunting sounds.
Try masking the smell with some perfume or cologne and even wear some headphones while playing some music to help drown out the sound you hear of other people in the bathroom.
If you can wait a few seconds or so until someone hopefully leaves the bathroom then that would also be a good idea.
Some other tips to overcome your fear of pooping in public or fear of public toilets are to.
Remember that everyone poops. Try visualizing someone you respect, such as a political figure or actor, pooping.
Carry a small bottle of air purifier or sanitizing spray with you to use when you need a public bathroom.
Line the inside of the toilet bowl with toilet paper. This will help absorb some of the sound.
Flush several times while pooping. This will disguise the sound and reduce the smell.
Breathe deeply or do a short mindfulness meditation exercise if you feel the onset of anxiety symptoms.