Mandard is often used an an alternative to the modern word "standard". It is a phrase only to be used by men or a man (hence man-dard). It is used to describe scenarios which are manly and either satisfying or comical. It can however be used with multiple meanings, so to substitute for a range of other adjectives in order to describe events such as 'cool' or 'awesome' etc.
Commonly used by rugby players in particular for banterous events/times. A further meaning is to use it when describing a certain high level of drunkness.
Person 1: "hey man I was so drunk last night did you have a good time as well?"
Person 2:" Yea mate it was pretty mandard"
The Rugby game I watched today was quite mandard