Mumu button indeed!

Sorry to digress
In term of sex, I have observed that male tend to be "mumucious" during two occasions:

1. when he meets the opposite sex of a higher class than he is
2. at the initial start of a realationship

But female can also be "mumucious" based on the first condition as in a male and also..

1. from the moment the relationship gathers momentum till it either dies or succeed.