There is 22 months between my daughters. We went to the local shop one day and the youngest - still a baby in her pushchair - started to cry, whereupon the eldest announced to the whole shop " mummy, mummy, the baby is crying - she wants some boob!" I blushed, as did the poor bachelor shopkeeper and the other customers just smirked and tried not to giggle!
The youngest got her own back though when they were aged about 6 and 8, by saying it a very loud voice in a cash and carry - "Mummy, see that boy over there? He wants to have sex with (other daughter's name!) Goodness knows where that came from, but wherever it was it was very loud!