Bowen Yang says he once attended conversion therapy just so he could end up at the "gayest school in the country" ... and the story from his youth actually has a pretty funny plot twist.

The 'SNL' alum sat down with Jason Bateman, Sean Hayes, and Will Arnett on their "Smartless" podcast and recalled his experience ... explaining he was "discovered to be gay" at 17 years old, when he forgot to close a chat window on the family computer.

Bowen said his parents were "sobbing at the dinner table every day" and eventually offered up an ultimatum ... he could live with them and go to a state school in Colorado or go to school with his sister at NYU, if he agreed to go to conversion therapy.

It's ironic ... Bowen says NYU was "the gayest school in the country."

He claims he spent 8 weeks seeing a "quack" in Colorado Springs who tried to convince him that any time he was attracted to a guy it was because he was "miserable" or "in pain."

But here's the gag.

In the last session, the specialist tells Bowen an anecdote about one of his former patients who caught a waiter making eyes at him in a Denny's ... the specialist accidentally slips into first person, telling Bowen, "And then I was like, 'Am I really going to have sex with this person?' And then I did."

Bowen says the man didn't catch himself shifting into the first person until it was too late.

The comedian's got a lot more wisecracks here ... so check out the audio.