"Mandrea" is a poor insult towards anyone with the given name of "Andrea." Albeit such may at first seem clever, the fact is that by calling someone this one is actually only displaying his own stupidity. For, the days of insulting someone's gender cease when one graduates third grade.
So, unless you are nine, or mentaly handicapped, the aforementioned word should be forgotten; as once again, it is pathetic.
No one should claim that the word "Mandrea" is funny.
Such is the case because the word "Mandrea" is not funny.
However, if one really feels it necessary to alter the name "Andrea," his best bet is to go with "Grandrea." This is funny until the "Andrea" at hand is admitted into an old folks home, then it is true, and consequently is no longer humorous.