Dr_skyhigh,
I learned to fly very close to a MATZ, so it was one of the first things we did. Introduce yourself and give your life history as usual, requesting MATZ Penetration. They will tell you when to switch to their QFE, and probably give you a squawk code, so it helps to be prepared for that. They'll also tell you when to switch back to your en route frequency, or possibly pass you on to someone else. It's usually very simple. Very very occasionally they'll use some military terminology you're not familiar with, in which case just ask them what they mean, in normal English!
Hope that helps.
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Whirly
To fly is human, to hover, divine.