Pardon 



That's possibly the most batshit thing yet.
If I'd tried it, I would have said 'Do you know when a stallion mounts a mare, ignore all you've seen & heard, it's actually called special cuddles and don't for heavens sake look too closely at how exactly the special cuddles happen'
'yes I know I have taught you all the other body parts and we can talk about exactly what the vet is doing with that tendon, but we're not going to discuss why exactly a certain part of the anatomy is involved in gelding'
'Yes, we can discuss breeds, colours, first aid, feeding, size etc but I'm not telling you the difference between stallions, geldings and mares'
I suppose I could have just shrugged when she then asked why some geldings still wanted to have special cuddles with certain in season mares. Perhaps I should have explained visibly in season mares as doing special wee wees.
In reality, at 4 my dd would have thought such a ridiculous explanation was a joke, and then told you in simple terms exactly how it worked.
Please tell me when you're talking about/ teaching dc the points of the horse you refer to your mare's foofoo, and your geldings wee wee stick, that really would be the icing on the cake of hilarity.