Shirako, as this excellent article by Leo Lewis in The Times explains, is one of the great - yet also to some unspeakable - seasonal Japanese delicacies: for many it's right up there with fermented sea cucumber guts, whale tongue and horse sashimi in the 'I wouldn't eat that even if it meant Simon Cowell experienced immense, searing pain' category of foodstuffs.
It is, let's be frank, no beating about the bush here, let's call a spade a spade, cod's sperm. We could call it 'milt' or 'cod whiting' or 'cod's wallop', but what it really is is a big bag of cod's seed.
As I once said to Queen Latifa when we encountered a large, locked gate while out rambling in the Cotswolds, "Get over it, girl".
Now is the best time to eat shirako, with the seas around Japan at their coldest. I've tried it in Tokyo, deep fried as tempura with fresh grated daikon and a drizzle of ponzu, and it was sensational. A little like oysters in flavour and texture, yet much creamier and without the harsh saltiness or metallic tang, perhaps the closest comparison would be with raw scallop corals. Delish.
So imagine how excited I was (we're talking clenched fists, jumping up and down, and high pitched squeaking noises here) to find a great bucket of the stuff in my local fishmonger. They were virtually giving it away as, clearly, for Westerners, there is something of a psychological barrier to be overcome in order to persuade them to swallow fish seed for pleasure. But not me, no siree. I love the stuff. I don't see the problem: if you are prepared to eat fish eggs, and indeed people will pay a couple of hundred quid for a couple of hundred grams of caviar, then why not?
I even fed it to my family, disguised as sushi. Happily, they didn't like it.
Of course, with cod stocks falling faster than Queen Latifa over that gate*, the idea of eating millions of potential fish does, ahem, prick one's conscience. But I have an answer for this: whenever eating shirako, I simply tell myself it was a gay cod.
Does that help?
*I don't even really know who Queen Latifa is. How did she end up featuring so prominently in a post about shirako?