Neptune is your collective psyche and what you're "addicted" to or how you seek escape.

Neptune in Aries (1861-1875) or 1st House	addicted to or seeks escape through action, speed, challenge, the self, war, conquest, aggression, force, leadership, innovaton, invention, accomplishment, self-acclamation, winning, promoting, etc.
Neptune in Taurus (1874-1889) or 2nd House	addicted to or seeks escape through money, wealth, land, possessions, ownership, productivity, resourcefulness, pleasure, beauty, affection, sensuality, sweets, song, dance, the arts etc.
Neptune in Gemini (1887-1902) or 3rd House	addicted to or seeks escape through knowledge, intellect, thought, communication, media, books, writing, speech, movement, transportation, connectedness, diversity, change, humour, etc.
Neptune in Cancer 1901-1916 or 4th House	addicted to or seeks escape through food, housing, security, family, roots, past, sentiment, feeling, emotion, conservation, preservation, history, tradition, recognition, remembrance, etc.
Neptune in Leo (1914-1929) or 5th House	addicted to or seeks escape through fame, glamour, power, pride, status, influence, creative expression, pleasure, fun, entertainment, love, romance, children, adoration, generosity, flattery, etc.
Neptune in Virgo (1928-1943) or 6th House	addicted to or seeks escape through work, duty, service, efficiency, order, detail, precision, perfection, purity, cleanliness, health, exercise, technology, ecology, environment, weather, etc.
Neptune in Libra (1943-1957) or 7th House	addicted to or seeks escape through beauty, harmony, balance, peace, marriage, partnership, association, pleasure, company, unity, co-operation, fairness, justice, law, mediation, etc.
Neptune in Scorpio (1955-1970) or 8th House	addicted to or seeks escape through sex and emotional intensity, death and rebirth, research, investigation, the occult, dealing with debt, taxes, legal(or llegal) matters, etc.
Neptune in Sagittarius (1970-1984) or 9th House	addicted to or seeks escape through God, religion, morality, spirituality, philosophy, culture, travel, adventure, sports, athletics, nature, animals, horses, publication, international affairs, etc.
Neptune in Capricorn (1983-1998) or 10th House	addicted to or seeks escape through status, achievement, rank, reputation, honor, tradition, work, career, management, order, control, economy, quality, quantity, time, definition, etc.
Neptune in Aquarius (1998-2012) or 11th House	addicted to or seeks escape through truth, freedom, independence, uniqueness, originality, futurism, idealism, friendship, botherhood, humanitarian goals and associations, etc.
Neptune in Pisces (2012-2027) or 12th House	addicted to or seeks escape through everything one should ideally be addicted to, such as rest, sleep, fluids, art, music, visualization, meditation, inner life, the principles of collectivity, universality, sacrifice, and forgiveness, etc