I write myself

1. HANDCUFFED.
Maybe one character has handcuffed themselves to the other on purpose. Maybe not. Either way, the cuffs are awfully sturdy and it looks like you've just lost the key.

2. TIED UP / CAPTIVE.
Being actually tied up isn't a necessity, although you're more than welcome to write it that way! The important part of this prompt is that the two characters are both being held captive by an outside force, one with less than benevolent intentions.

3. TRAPPED INDOORS.
The classic "snowed in" option, although snow isn't the only option! Any sort of intolerable weather works, and there are always more creative options, like being trapped in an underground bunker during a nuclear winter. The world is your oyster.

4. ACCIDENT / RUBBLE.
A collapsing building pinning two people down gives ample time for a bonding session. Or screaming for help. It's up to you.

5. AN ISLAND / THE WILDERNESS.
Whichever location you choose, it's deserted save for two. They'll have to fight over the meager resources there are or work together to survive until they can return to their homes.

6. IN SPACE.
Maybe someone just pulled a Passenger and woke another passenger from their cryopod, or maybe all the others in your crew died and they're the only ones left. In space, you're really, truly alone.

7. TWO MAN JOB.
They're not physically trapped together, but there's a job that only these two can do. Maybe they hate each other, but hate a third party more. Maybe they've been stuck together on a mission by a superior. The possibilities are endless, so don't be afraid to get creative.