Ashley Kaidel is encouraging other mums to "nurse uncovered" and not feel ridiculed simply for feeding their baby.
The mum from America uploaded a photo of herself breastfeeding her five-month-old son and staring off to one side.
"It appears I'm staring off into the distance. In reality, I'm staring into the eyes of a woman staring at me," Kaidel wrote.
Kaidel explained: "She is looking at me with disgust and shaking her head with judgement in an attempt to shame me and indirectly tell me without words that I am wrong and need to cover myself.
"So let me make my reasoning clear on why I post pictures of my son and I publicly breastfeeding uncovered."
Kaidel explained her post wasn't intended to put pressure on mums to breastfeed without a cover if they don't want to, but she wanted to encourage mums who are worried about feeding their baby in public for fear of judgement.
She continued: "The reason I post these types pictures is for the mother that tried breastfeeding uncovered once and she got shamed, she got stared and pointed at, she got nasty comments, she got asked to leave the room, she got asked to cover up.
"Breasts were made to sustain your baby's life before they were made to bring pleasure to any other man, woman, partner or spouse.
"Their sole purpose is to make food and dispense it straight into a baby's mouth. There is nothing weird about this and there's no difference in me feeding my baby with my breast than you feeding yourself with a spoon."
The mum said it's unfair to shame a mother for feeding their baby at a table, saying if people don't want to see it they should look away.
Kaidel also said children seeing women breastfeeding is not harmful.
She wrote: "[Children] need to acknowledge, comprehend and appreciate that breast milk and breastfeeding is and should forever be the first and best choice for both mum and baby.
"Your 11-year-old daughter watching me nurse may say 'Mum, why is that baby sucking her boobie?'
"But as a parent and human being that understands, respects and appreciates anatomy and mothers, your reply should only and always be 'because that's the way babies eat'.
"I didn't post this for attention. I didn't post this because I think everyone should nurse uncovered.
"I posted this to give mamas encouragement and to encourage others to make breastfeeding mothers feel accepted and supported; not alienated, ridiculed and judged."
The post, which was uploaded on 25 November, has had nearly 95,000 shares and thousands of comments from mums in full support.
Breastfeeding women have posted their own photos of themselves feeding uncovered in response to Kaidel's post.
"Some babies won't breastfeed covered, no matter what," commented one mum. "So a mum makes a choice to feed her baby or avoid criticism. A great mum always chooses her baby. That should be applauded, not shamed."
Another mother wrote, alongside a photo of herself breastfeeding: "This is the most beautiful experience I have ever seen.
"I love seeing a confident mum sit in a public place and not be afraid to feed her baby.
"If you don't want to see a boob or don't want your kid to see it... don't look or stay home and cook. We will not stop feeding our babies because of ignorant ass people."