Here is what I suggest, park him a bit behind you, off follow etc but still facing the mob, then Frostbolt the mob, frost nova, run,jump turn then frostbolt and fireball, the other mage will remain now a bit in front of you, probably next to the mob, facing him and able to fire away. Otherwise position him to the side.
I am a frost mage my self, let me give you a tip where you can do 5K dmg in one cooldown with about +-700 spelldmg.
Start pull: Frost bolt, frostbolt again. Mob is near then frost nova. Turn and blink away, turn to face the mob.
Cast frost bolt but then 2 seconds before frost bolt is sent, SPAM the hell out of icelance, and you will often see frost bolt and icelance sent at the same time.
If you specced frost properly, your frost spells will have an increased 75% crit chance or something like that.
This means that anywhere from 80-100% your spells will proc.
Normall I do an average 3.2k frost bolt crit + 2k icelance crit (=5.2k + the 2 previous frost bolts, there fore +- 7.6k dmg..) If this doesnt kill them fireblast, no need even for fire mage. Otherwise make it so that you have 4 frost bolt macros
e.g.:
Key board button:| Frost mage: Fire mage:
Think of it as a table.
______________________________________
1 | Frost bolt | N/A |
______________________________________
2 | Frost bolt | Fire ball |
______________________________________
3 | Frost bolt | Pyroblast |
______________________________________
4 | N/A | Pyroblast |

Now if your starting your pull, Press button 4 or 3
Then once pull has initiated Press either 1,2 or 3. By this time the mob should be dead, then just do a dual fireblast. (You could make it all button1 on keyboard but just say 1, shift+1, ctrl+1 etc)
Just play around with specs and spell combos, remember that it might help to say bind AWDS to your mains movement keys then Left, Right,Up,Down arrow buttons to alt movement keys, so if you alt is slightly off target just hit Left or Right arrows.
Also remember frost nova and sheeping is your friend, but honestly if you are 2 mages, the mob should go down in 2 ticks, Also you should soon get ice shield etc, doesnt matter if a mob touches you, just spam arcane explosion and it will die before your shield runs out.

I do the "park alt off behind me or somewhere near" method when I aoe farm with my mage and resto shaman. I just have my shaman as alt and pop ES on mage, and pop him and totems in a clear spot, agro all the mobs on the mage, bring them nearish to shaman then Iceblock (ES wont put the shaman in combat), frost nova, blink away, then have blizzard and arcane explosion marcos that will also make my shaman cast lesser healing wave on me (downranked to generate less agro).
So basically i get 1 or two blizzards in then just run in an arcane explosion, normally my shield holds but if it doesnt i got ES and healbot on me, helps ALOT.