The debate exists because idiots are porn-brained, lol.
Of course it's all just piss. It's always been just piss. But it's especially just piss for men. For women at least it's a mixture of piss and fluid from the skene's gland.
It's hilarious because if you read any of the medical research or just read accounts from actual porn actors they all say it's piss, lol. Literally all the experts agree it's piss but these fucking authors keep doing it because they're writing porn for women by women and they're just drawing some of the characters as men.
This man just pissed in his partner's ass and gaslit him about it.

Men physically can't squirt! That's just piss.
Men don't have a Skene's gland. Men can only cum or piss. Men can cum so much that it becomes watery and doesn't have very much semen in it but it's still just cum and the mechanism is the same as cumming. Men can also cum with more or less prostate fluid in their cum, but it's still cum and all cum has prostate fluid in it.
I'm saying this assuming the man is healthy, there's always going to be health issues that can cause you to have more or less of any sort of fluid in your fluid, but that doesn't change the mechanism that makes the fluid or what the fluid is. Cum without semen is still cum and cum with extra prostate fluid is still cum.
I hate how these authors try to make men into women because they're writing this for women. Please at least get male anatomy right if you're going to write about men.
Before you argue with me because you are porn-brained and learn everything you know about the human body from porn, please go research it. The vast vast vast majority of medical information about this states that it's not possible for men (the vast majority of research into it also says that it's not possible for women and it's just piss for women too, but women at least have the skene's gland so there's at least an argument that can be made.)