This is about the only sensible explanation for how Anakin destroys these missiles in the movie. He goes into a spin, and the missiles start spiralling around one another in tight helical paths.

Apparently in the Star Wars universe, homing missile designers totally over-engineer the capabilities of the missiles, until they're so stupidly precise and accurate that this sort of thing can happen. I guess that's where they put the designers who start overthinking their designs and adding superfluous features like safety railings on all those bottomless-pit-spanning catwalks.

Transcript

Missile 2: You seem like really cool dudes. And boy, taking out one of those fat dreadnoughts would have been really righteous. But hey, fast fighters, that's where the action is.
Missile 1: Tell you what, we'll let you choose where we hit you.
Anakin: Okay, you take my left engine.
Missile 1: Cool, man. It's been awesome hanging with you.
Anakin: Other missile, the right engine, if you please.
Missile 2: Ooh, symmetry. Rad.
[SFX]: Whoooosh!
Anakin: Are you locked on?
Missile 1: Yep.
Anakin: Right. I go into a tight spin.
{the missiles spiral around each other as the follow Anakin's spinning ship}
Missile 1: Wooooah...
Missile 2: The stars are making circles...
[SFX]: Whoooosh!
{the missiles collide with each other and explode}
[SFX]: Kabooom!!!
[SFX]: < beploop bedoop >
R2-D2: How depressingly stupid.