The Irish actor Domhnall Gleeson may be in every other movie in theaters these days — “American Made” for example. And “Mother!” And “Goodbye, Christopher Robin.”

But you’ve never seen him in anything remotely like “Crash Pad,” as a hapless young lover with that Irish “gift of the gab,” weepy/chatty, drunk and pathetic, trapped in “wing-man” mode with the swaggering stud on sex patrol (Thomas Haden Church).

It starts badly. Stensland (Gleeson) has just bedded Morgan (Christina Applegate). Actually, she’s bedded him. The weekend ends and it’s “I’m married” and “This is the last time we will ever see each other.”

And Stensland doesn’t take that well. He’s a romantic, and a bit of a tantrum tosser, with a way with words.

“I’m not some DILDO you wipe off and put back in the drawer!”

He threatens blackmail, even as he’s hurtling into a funk of hurt and rejection. His old roommate may ponder his problem with “sex without strings” with a hot older woman.

But Stensland is inconsolable — “I WANT strings!”

He barely has time to settle into his “Dawson’s Creek” weep-and-binge session, right after his in-the-mirror affirmation –“You’re not the smartest. You’re not the best looking. But you’ve got something that attracts the ladies!”

Because he pushed the blackmail onto Grady, Morgan’s husband. And after the death threat and gun-pointing conversation that follows, the wealthy lawyer and cuckolded husband (Thomas Haden Church) has decided he’ll move into Stensland’s cluttered “Man Shed.”

“But you just said it ‘looks like a pirate ship and smells like beef noodles.”

“It smells like ‘MAN.'”

Thus is the weepy romantic trapped in a Seattle flat with a testosteroned alpha male, determined to obtain revenge sex with a stranger to get back at his wife, and hellbent on making a man out of Stensland in the process.

Bar hopping, frat party crashing pursuit of coitus ensues.

“Survey the showroom. Pick out a model. Take her out for a SEX drive!”

Yes, it’s an R-rated “How I Met Your Mother,” without the mother. But the Jeremy Catalino banter sparkles, with Gleeson gifted with assorted tirades, manifestos and shrieking lectures (to frat boys and the compliant “little sisters” who show up for their beer busts).

“What is WRONG with you people? This isn’t FUN!”

It’s no surprise that Church jumped into this, and his “Sideways” director pal Alexander Payne got this Kevin Tent film made by taking a producing credit.

Church and Gleeson are hilarious as a love/hate threat-of-violence pair, with a manic chase (Gleeson endures a few nude scenes) and a lot of “be a man” lectures, starting with getting those damned “Dawson’s Creek” tapes out of the VCR.

“Find a sporting event, or something with car crashes.”

Applegate gives Morgan an amusingly irked professional woman’s vexation at her husband and lover setting up housekeeping. And Church is an old hand at this Basset Hound expert on chasing women, and catching them.

“You know what happens when vexed women start thinking? Civilizations FALL!”

The bars are peopled with oddball lovelies who resist the lads’ charms, ordering their “Harlem Mugging” cocktails and talking about their dead ponies. Gleeson’s Stensland is given a wide Seattle support system, from the ex-roomie to the understanding folks at his “safe space,” Soft Solutions Fine Furniture, who let him come in, weep and sleep in their chairs.

I loved the running gag that lets him tell-my-woes-to-sympathetic ears bit that has him sharing drinks and confessing his broken heart to a trio of 40something female black barflies, a hilarious contrast (the ginger-haired Gleeson could not BE whiter).

Nina Dobrev plays Morgan’s man-wise assistant and sounding board, too cute to not be a love-interest for Stensland, too out-of-his-league to give him the time of day.

None of which adds up to much that’s surprising, but is still funny in performance. Even the “that’s my JAM” drunken dance scene is cute, a chuckle mixed in with some very big laughs.

But here’s a memo to ’80s pop star Billy Ocean. If you’re offered a cameo in a comedy produced by Alexander Payne, you take it (another actor plays him). And if they want the rights to “Get Out of My Dreams, Get Into My Car” for a drunken romp/dance scene, you tell them “Loverboy” would work better.

MPAA Rating: R for strong crude sexual content, language, some nudity, drug use and alcohol abuse

Cast: Domhnall Gleeson, Christina Applegate, Thomas Haden Church and Nina Dobrev

Credits:Directed by Kevin Tent , script by  Jeremy Catalino. A — release.

Running time 1:32