Multi personality disorder, or DID dissociative identity disorder, is a mental illness in which the person has 2 or more personalities inside one mind. It is often caused when a child is repeatedly sexually, mentally, or physically abused and cannot physically escape the situation.

Mercury retrograde is the act of taking a shit whilst mooning one or more human beings. Your day can typically being going well, according to your horoscope, until you are forced into witnessing Mercury retrograde. Performing Mercury retrograde will often speed the astrological cycle forward for the individual performing the Mercury retrograde, bringing about happy and fruitful times to come.

Mobile Pornography Device

Multiple Personality Disorder: An extremely rare mental disorder where a person's mind is split into two or more personalities that attention-desperate teenagers pretend to have so people will think they're unique/cool/troubled/not a loser, etc.

MPD also known as "Malarian Penis Disease" is a sexually transmitted disease, which is usually received when one has sex with skanky girls; specifically ones that "Fat John" has been with.

Acronym for "Mega Power Dump." Announce or shout this when you are in the midst of toilet warfare.