Moon square or opposition Mercury
There is a conflict here between the head and the heart. The emotions tell them one thing and the mind tells them something else. The result is a wavering, and a see-saw effect is most evident with the opposition–emotional to the point of irrationality at one moment, and logical the next. How to blend the head and the heart is a constant struggle for these individuals, usually because there is a tendency to resist blending them!
These people love to chat, enjoy story-telling and writing/poetry, and usually possess a sparkling wit! They are animated when they speak, and have a sense of humor that others appreciate simply because it’s very imaginative. Some are especially adept at satire. You can usually tell their moods by how much they’re talking. When nervous or excitable, they talk up a storm. Moodiness is a characteristic, definitely, and an especially subjective nature makes them prone to hypersensitivity. It usually has to do with the fact that they take in so very much from their environment. This is also one of the reasons why they tend to be indecisive. While Mercury conjunct Moon people tend to be quite consistently rational, the hard aspects of Moon-Mercury generate a swing between irrational and rational thoughts and feelings. This rarely transfers into action, however. It’s pretty much something that takes place “upstairs” in the mind, although others are sure to see the struggle from time to time. These people are always interesting, and usually funny. They have a tendency to misrepresent themselves with what they say from time to time, but they’re charming, if a little kooky, friends. Source: http://www.cafeastrology.com/natal/moonmercuryaspects.html