Transit Mercury in Aspects to Natal Neptune

Natal Neptune is the sign where your Neptune was placed during birth time, and from there other houses are calculated clock-wise.
If you were born with Neptune in Sagittarius, then your natal house is Sagittarius (Dhanus Rasi) and during transit, MERCURY forming conjunction (in Sagittarius), sextile (aspect of 60° which are Libra and Aquarius in this case), square (aspect of 90° which are Pisces and Virgo here), trine (aspect of 120° which are Aries and Leo here), opposition (aspect of 180° which is Gemini here) are discussed in this article.
Conjunction is transiting through same sign as in birth chart, sextile is transiting 3rd or 11th house, trine is transiting 5th or 9th house, opposition is transiting 7th house from natal sign.
MERCURY transit Natal Neptune

Transit Mercury conjunct Natal Neptune : Creative expression and intuitive imagination in artistic and literary fields are the key notes of this transit. Actually this transit has two-fold effect, one creative and the other difficult. On the positive side one is able to express his ideas and feelings with greater clarity while on the negative side the ideas and thinking are confused and others are not able to comprehend one’s ideas. Afflictions to the conjunction result in distorted conscious reasoning based on subconscious biases and prejudices like wool gathering, day dreaming and uncontrolled imagination. On the positive side telepathic and clairvoyant faculties are enhanced to help designers, mathematicians, scientists, and artists. The native has prophetic insight into future events and trends. The native is interested in parapsychology or mysticism, occult or spiritual forms of healing. If the individual is not cautious then susceptibility to dietary changes, drugs, alcohol or medication can be disastrous. There is also susceptibility illness hard to diagnose. Under stress aspects this transit is more undesirable and the native may be subject to deception or confusion in communication.

Transit Mercury Sextile Natal Neptune : Clear insight into subconscious mind and enhanced intuitive awareness characterize this transit. This is favorable transit for the study of metaphysics, and the native is a channel for information from a spiritual source. The individual may be able to comprehend what is going on in others mind and may use it for his own benefit. A good period to study religion, spiritualism, occultism, and mysticism and the individual may have short trips for work in hospitals, asylums, temples and other such institutions.

Transit Mercury Square Natal Neptune : Distorted fantasies and subconscious reasoning characterize this transit. A period of considerable confusion and the native is misunderstood for his inability to convey his thoughts properly. The native is inclined to be secretive which can be troublesome for him. Misuse of drugs and medication can be disastrous. However the native can progress in mystic, occult and spiritual subjects. This is not a good period for any kind of serious work as there is a tendency to notice some facts and ignore the others dictated by subconscious emotional prejudices.

Transit Mercury Trine Natal Neptune : Clear intuitive awareness and telepathic abilities and stimulation of imagination characterize this transit. The increased imagination and intuitive ability can be used to solve the professional and work related problems. Also a good transit for writers, poets, artists, actors, psychologists, occultists and musicians. The native may relate himself to the works of spiritual healings and may engage himself in hospitals, asylums and religious retreats.

Transit Mercury opposition Natal Neptune: Mental confusion, blurred intuition, day dreaming and weird psychic experiences characterizes this transit. The native is subject to absent mindedness. The individual exhibit deceptive and misleading tendencies generally. The native pretends to be ill to avoid responsibilities. The native has a tendency to postpone the work for tomorrow. Misuse of drugs, alcohol, or medication may worsen the health and usually illnesses are hard to diagnose at this time.