If you desire to force an over-shoot on a P-38, the 109 is particularly adept at a certain manuever which involves chopping throttle, rolling left, using hard left rudder and full 'negative' elevator input (i.e push forward)
This results in a rapid loss of speed. If you slow the roll initially, the 38 may be stupid enough to try and roll with you, thinking you're just trying to turn and escape. Speeding the roll up when you see the 38 start to roll with you will then hopefully result in him losing site of you and over-shooting.
Of course, in this case it is desirable that the P-38 has a 'medium' E advantage, IE, he is gaining on you from high-6 or even just dead-6. Provided the 38 is not too slow or massively fast, you'll be able to roll out behind him, firewall the throttle and then lob a few 'taters' at him.
Failing the kill-shot, you should be at least able to evade his sight for a moment... just long enough to extend and escape or start again.