When an audience gets hit with a sustained case of the giggles, how can you adequately describe what’s causing it on stage? Because in “The Pajama Men: Just the Two of Each of Us” at Woolly Mammoth, it’s not much. Just two guys in pajamas, zipping through bizarrely linked skits and talking in funny voices.

One of many happy meltdowns occurs during a loopy breakup scene, with Mark Chavez wagging a finger and declaring it’s over while Shenoah Allen grins stupidly and pleads. It’s ridiculous, but the warp-speed delivery and bubbly variations on the refrain are irresistible.

So are the puns and one-liners, like the one about boomerangs being “the lonely man’s Frisbee.” (They’ve got a million of ’em, folks.) This is quick-hitting, no-frills street theater: There is absolutely no set, and other than two chairs, they don’t even use props.

Yet you’ll swear you see everything from spiders and crowns to speeding cars as they tear through characters who always come in twos, fleeing village-destroying monsters (for instance) and peering into enchanted sinkholes. All the characters eventually get caught up in the same plot, and while that’s hardly necessary, it works as a way to put a button on all the mayhem.

You can see the wisdom of the PJs: Wearing such generic and basically silly outfits, it’s easy to sustain their game of let’s pretend, which is actually something that two drawling dames named Diane (Chavez) and Nadine (Allen) play early in this show. Sporting sleepwear and bed heads, Chavez and Allen look like guys who abandoned the frat house about a decade ago and have figured out how to avoid getting fully dressed ever since. Like Hugh Hefner, only different.

Promotional photo for the production Pajama Men, starring (from left to right) March Chavez and Shenoah Allen. (Steve Ullathorne)

The bits fly by, and the clowning is polished to a high shine. Both men are preposterously limber and physically precise: Note Allen’s dexterity as he fiddles with an imaginary prosthetic arm that becomes one of the evening’s best running gags. And behold Chavez as a horse, especially when Allen, playing a character in a moment of high distress, tries to steal a comforting kiss from the beast. The nervous look on the horse’s face — well, you can imagine.

The show’s only other theatrical adornment comes courtesy of Kevin Hume, who provides live music on acoustic guitar and keyboards. Hume’s underscoring is marked by a kind of low-key delirium; more often than not, it’s a martini-dry take on old spaghetti Western scores.

This is the second straight year the Pajama Men have filled the holiday slot at Woolly, following “In the Middle of No One” last December. Their jam-packed act is pretty danged jolly, and the 70-minute length is just right.

The Pajama Men: Just the Two of Each of Us

created and performed by Shenoah Allen and Mark Chavez. Music by Kevin Hume. Lights, Mary Keegan. Tickets $35-$82.50. Through Jan. 5 at Woolly Mammoth Theatre Company, 641 D St. NW. Call 202-393-3939 or visit www.woollymammoth.net.