Like I mentioned earlier, If you've got a good stick on your six the likelyhood of shaking him is low. In theory, If you've got two or more even averarge sticks on you they should be able to beat you. In practice you can often turn the tables.
You need to maintain a constant series of turns, loops and rolls preferably reversing from one opponent to the other and your moves need to also be unpredictable. Many fall into the trap of always turning or rolling to the left for instance, which becomes a predictable move and sets you up for a snapshot or deflection shot.
You'll need to become really good at taking instantaneous snapshots as your opponents cross your nose. The likelyhood of being able to saddle up on one's six is low and if you find that you're able it's most often because he's setting you up for his friend.
The best advice is not to get yourself into these situations to begin with. Only get in deep enough where your skills can get you out although I realize that it's sometimes unavoidable.
The best way to get good at this is to practice and die. I find myself gleefully diving into a pack of 5-10 enemys alone knowing I'm going to die but also anticipating the adrenalin rush that I'm about to experience and if I can take two or three before I go down I've had a great flight. I've got squad mates and countrymen who question my sanity and hover above the fight or reluctantly join at my urging but I feel it makes me better every time I die doing it and, like I said, its a blast.
Have fun with it. In time the practice will teach you survival.