An Idaho school board trustee is facing calls for his resignation after telling Gov. Brad Little that he will be “pissing on [his] grave” for outlawing gender-affirming care for kids.

“F–k you @GovernorLittle,” tweeted Shiva Rajbhandari after the governor signed a bill that threatens up to 10 years in prison for anyone giving hormones or puberty blockers to those under 18.

“I pray you live a long life so you can bear witness to the pain you’ve unleashed on Idaho’s children and families today,” wrote the Boise School District board trustee.

“When you do die though, I’m pissing on your grave.”

Rajbhandari — just 18 and the first-ever student to serve on the school board — maintained in a follow-up tweet that the “law is unconstitutional.”

“When government begins to intrude on the inalienable rights of the people, it forfeits any form of legitimacy,” he wrote.

“It is not just our right but our duty to stand up to tyranny. We will never EVER stop fighting for our trans and non-binary youth.”

By Friday, more than 250,000 people had viewed the missive, with a smattering of people supporting it — but the majority ripping his response.

“Fire this person,” one person demanded, while another called him a “psychopath.”

By the end of the day, Rajbhandari addressed the blowback to his angry tweet, noting those who felt it was “inappropriate and inconsistent with” his trusted position on the board.

“Sometimes we need to feel all the feels and say what we’re really thinking,” he said, stressing that his message was his “own” and do not necessarily reflect the views” of the many groups he is affiliated with.

“My strong language is reflective of my anger and frustration with the pointlessness of diplomatic dialogue with legislators and a governor who have shown such little regard for the lives of Idaho youth,” he wrote.

“The hypocrisy of suggesting that a profane tweet is more harmful than what HB 71 could unleash on our trans and non-binary youth baffles me,” he said of the bill Little signed into law.

“I remain unapologetic in my commitment to our LGBTQ+ community,” he wrote with a power-salute emoji.

That, too, received a mixed response, with some commentators sending “respect” and telling him to “stand firm” — but others demanding: “RESIGN.”

“Your [sic] not walking this back. I won’t allow it. You need to resign,” one person replied.

Neither Rajbhandari nor Gov. Little’s office immediately responded to The Post’s request for comment Friday.

Idaho is one of at least 13 states to enact a law restricting or banning gender-affirming care for minors, and nearly two dozen more are considering similar bills.

In his signing statement, Little noted how lawmakers need to “take great caution whenever we consider allowing the government to interfere with loving parents and their decisions about what is best for their children.”

However, “in signing this bill, I recognize our society plays a role in protecting minors from surgeries or treatments that can irreversibly damage their healthy bodies,” the governor wrote.

Little’s spokesperson Madison Hardy said the office had received nearly 20,000 messages from supporters of the legislation by late Tuesday — as well as more than 11,500 from people urging him to veto it.

“This bill is about protecting children,” said Republican Rep. Bruce Skaug, who crafted the legislation with the Idaho Family Policy Center, a Christian lobbying group.

The American Civil Liberties Union of Idaho announced Wednesday that it was looking for potential plaintiffs for a lawsuit.

“For lawmakers to interfere in decisions that ought to be made by families and their healthcare providers is clear government overreach and is unacceptable,” executive director Leo Morales said.

The LGBTQ+ support group Add the Words Idaho said it has been fielding “frantic” calls from despairing families.

“We are watching parental rights being dismantled in the name of stigmatizing and harming our most vulnerable youth,” said its executive director, Chelsea Gaona-Lincoln.

“The fear in parents’ voices is real as they do not know what to tell their teens or how to provide them with hope while their elected representatives actively attempt to legislate them out of existence.”

With Post wires