Contra Body Movement Position
No need to go into too much detail as you're a beginner but:
As you walk normally when you step forward with one foot/leg to opposite hip compensates by moving forward a bit too. That's CBM or Contra Body Movement. The opposite would be like a penguin walk with the hip and leg on one side of the body moving at the same time.
With CBMP or Contra Body Movement Position you can intentionally create a CBM type action by placing one foot forward or behind the other foot so that a straight line in effect can be drawn through heel-toe-heel-toe of both feet and creates the appearance like you get with CBM.
CBMP is often used when one partner is preparing to step outside the other.
(Hope I got that right everyone! ;^0 )
OB