When to Explain Female Biology to Boys

We had a similar sort of incident at the zoo several months ago. My son (then 5) was asking about the tampon machine... I said it was 'lady stuff' and tried to keep it vague. "But what for?"

"Well, remember that babies grow in a special place called the womb?"
"Yeah"
"Well, the womb is full of fresh blood every month to get ready in case a baby comes there. If there's no baby, the blood sometimes comes out. It's okay, it doesn't hurt or anything,it's just to keep the womb clean. So, women use things (I didn't go into detail) to keep clean while the blood comes out so they don't have messy underwear."
"Oh, okay."

I'm also at the point that he can wait outside the restroom or stall-- he's six now and while I'm frank about some things, I am asking him to respect my privacy and that's worked well. FWIW, unless he remembers and asks again, I'm not sure I would follow up right away-- he may have forgotten about it. But if he asks, keep it simple, don't get too technical, and reassure him. I only answer my son's questions specific to what he asks. Every family is different, and this is what works for us.

Honest thoughts-please don't take this the wrong way, but you had an opportunity to explain some things and at least answer his question, but instead you let your own discomfort win out, lied/avoided his question and shamed him for seeing anything and asking questions.
Go to him and start by answering his question about the tampon string. Allow him to ask the questions that he has and be honest. You're going to have to just get past your discomfort about talking about vaginas and menstrual cycles, so your boy learns about anatomy from you and not from his friends.
Good luck!

It's really hard to know what to say, especially when they catch you off guard (and they usually do). I agree that it's best to give truthful answers, but to also be as simple as possible. I try not to answer more thanks asked. If I don't give enough info, I'll be asked another question. Sometimes it feels really good when the next question is, "Can we watch a movie when we get home?"

Two tricks I learned to make it easier, especially if you need a moment to think. You can always say, "We'll, what do you think?" though I don't think that would have helped in you're particular situation. Another good questions, "What do you mean?" I've used that one several times, and the question they are asking is usually not nearly as scary as I first think it is.

We have to be prepared to talk to our boys, especially if they come into the bathroom with us. My son, who is 6, knows I get my period. That's it. It's something that grown up women get every month and it's how their bodies work. It was a basic explanation that worked for him. If he needed more details, I'd give him a few more. I'm planning on hitting the library for age appropriate books to help on this.

Do some googling or hit the library so you can get some "coaching" and you'll be ready for the next opportunity.

I think you might as well explain it to him. Buy a book if you're not comfortable.

If he's old enough to ask he's old enough for an answer. He doesn't need a Masters and Johnson seminar, but a simple, "It's called a tampon and it's something women use. I'll explain more when we get home." would have been fine for the moment.
When you got him home, you could have simply told him that every month a woman's body makes itself ready to have a baby, but if she doesn't get pregnant, then her body has to get rid of all the extra blood and tissue that it stored up for a baby to use, and so she bleeds. The tampon just absorbs the blood and keeps it from getting all over her clothes.

If he is asking at 5, I would answer honestly about female cycle. It's not a big deal. Keep it very basic.

- babies grow in a uterus. (there are very basic simple picture books in the library about this for this age group)
- the body releases an egg every month and the lining of the uterus starts to build to hold a baby.
- if there is no fertilization (up to you if you want to explain fertilization - plants, animals, people) the uterine lining starts to shed (it's not blood) because there is no baby there.
- perfectly normal and nothing scary
- the tampon (or pad) is there to catch the shedding so there is no mess