Nephew, niece, niece.
So first they went paddling, then they thought it would be a good idea to strip down to their knickers and go sea-diving off a groyne, which they did.
When they'd had enough of that they wandered onto the beach again to kick sand at and plant freezing little paws on their Uncle Chertiozhnik, just for laughs. Which they did.
Only after that did it strike them that they were cold, wet, covered in sand, and nobody had brought any towels or dry clothes.
That is why Grown Ups were invented.
Me, I went for a coffee and a cigarette (gets the sand grains out of your teeth), grateful that the Grown Ups were sorting everything out.
Later, at lunch, the middle child noted how much butter I was plastering on my bread and cunningly asked me to butter hers too (oh help!). Her parents (bro and partner) scrape some on and then scrape it off again with a religious air. Chlorestorol, d'you see? Me, if you can see how the butter is defying the laws of physics by leaning against some other substance, you haven't got enough butter.
I passed her back a properly buttered piece or two of whatever.
That's what Uncles are for, I told my brother.
"Indeed", said my bro, in a rather (I felt) old-fashioned tone.