To be annoyed SIL showed DS her lactating breast

Weeing and breastfeeding are very different.

If you can’t tell the difference between a man peeing and a baby feeding then you’ve got bigger problems.

It's extremely unlikely he will remember, it's not very interesting for a small child. Only about as interesting as the 1000 other things they will be momentarily curious about that day anyway, most of which will be absorbed into general knowledge and the details forgotten.

My eldest only stopped breastfeeding when he was 4, people on MN were convinced he would remember it and freak out. I had two more children when he was 10 and 13 and with the youngest he asked how long children usually breastfeed for and I said it depends, DS1 said he didn't even know he was breastfed at all, just assumed he'd had milk from a bottle.

You're being utterly ridiculous

It’s kinda cool though. Cool that we can produce food, and education. Little kids literally lap that stuff up! In some cultures your 4 year old would still be drinking your milk so it isn’t that weird, just in our culture it feels weird.

Hell no. Explaining the process is fine but she crossed a line squeezing her breast without consulting with you first. I don’t care how natural it is that doesn’t give someone the right to do that in my opinion

I think when you’re in the breastfeeding era you can lose your perspective a bit. I had no qualms about feeding at family events or anywhere my baby needed feeding. I got pretty annoyed when my mother asked me to feed in another room because my sister in laws father was there. I thought it was ridiculous. Now, years later, I can’t imagine popping a breast out (although I was always very discreet) in front of all those people and I understand my mother’s request. But at the time I was just feeding my child and I felt no reason to hide it. I can understand your discomfort with it but I also think she was simply answering a child’s question, which often involves demonstrating. I would not assume any intent other than to help him understand.

So to your own kids. Not to kids that are related by marriage?

It is boundary crossing to many of us.

Agree with OP, it was totally unnecessary. She should have asked you first if she wanted to show him.

..and there we have it - the idea that breastfeeding is a toilet function that should be kept private.
This reminds me of when I was breast feeding my first baby who is now in his early 50's. I was standing by the sinks in a women's public restroom, feeding my baby, when a woman told me that it was something I should be doing inside the toilet stall. Sitting on a toilet I guess!
At an airport women's room, a woman came up to me to see my baby, only to realize he was breastfeeding. Shocked she said, "shouldn't you be doing that in private"? I was also told by a woman, on another occasion, breastfeeding was "animal like". When a woman told me I shouldn't be feeding my baby in public. (I was always very discreet). I told her it was only natural, she said, 'so is shitting, but people don't shit in front of each other'.
Here we are in 2026 and some women still don't see the difference between nourishing your baby, as humans have done for thousands of years, to a man pissing in front of a little girl and then exposing himself to her.

I have definitely done this to show mine when feeding smaller ones. It’s not weird. It’s nice for kids to know that milk doesn’t grow in plastic bottles in Tesco.

It is so strange that people are pretending OP can't find this boundary crossing and unnecessary and pretending that breasts are absolutely unsexual when the fact is they can and do stimulate sexual arousal during adult foreplay.

I guess if someone has no real argument or answer, the best they can do is to gaslight and be sarcastic 🙄

Also totally agree

What a stupid comparison. Everybody on this planet wees, including this hypothetical daughter.

Relatively few people in our society BF for any meaningful length of time, and so it is never normalised for children. Your DS is going to grow up into a man who one day might need to be a supportive partner for a BFing woman. I think he was bloody lucky to have the opportunity to see it.

I’m not being weird or name calling as you have stooped to and wouldn’t have the audacity to ask anyone to “stop it”

Agreed

No, you're not keeping up at all. Oh dear.

So, is your cucumber attached to your body and does it stimulate sexual arousal during adult foreplay when sucked.

No, but a breast can and does.

It's just not that complex. Your initial "breasts are not at all sexual" was wrong.

You're welcome.

Don't let people say breasts aren't sexual. Of course they are. They are ALSO functional. Why are people gaslighting on this point?? Anyway, OP, I'd have been like you. Totally not needed. Not sure there was any harm but wasn't necessary.

I can keep up and that’s a ridiculous proposition…so cucumbers must be sexual in your world ..because they can be used sexually?

It was not her place to give him a “show and tell” on breast feeding.
Fine to breast feed around him, talk about it, but not showing milky nipples to a 4 year old who you didn’t give birth to.

I’m not angry ..I think it’s peculiar to be so exercised that SIL answered a child’s question in a way they could understand…you’d rather he thought the baby was eating her flesh?