the double team

For interior linemen, I teach two techniques, but with both the key is get a push on the "post man" (The OL that you are lined up on) and keep hands engaged on him. Once you feel pressure from the double teamer, you can do one of two things: 1) Drive your hip into the double teamer and "sit on the toilet". This makes you strong against his pressure. Very good for holding up against the double team and keeps the OL from working up to LB. 2) You can drop to your knee on the double team side and pop up. This allows a quick split of the double team and puts you in position to defend your gap. This is an easy technique to rep in mat drills, hitting the knee and popping up.
For DE's, I teach the knee drop, but I have also taught to seat roll into the double team. The doubler generally falls off and you pop to your feet where they are trying to run the ball. With all these techniques, the worst case scenario has been to create a pile and force the ball to bounce outside. I am sure there are other ways to teach it, but this has worked for me.