Past lives are usually associated with the 4th, 8th, and 12th Houses, being the natural domains of the psychic water signs. Each house may represent how closely involved, or in which specific ways your incubis/succubis have a role in your current life or past lives. For example, planets within 4th/aspects to 4th house ruler, implies the succubus/incubus helped you cope with circumstances in your private life, or allowed you to have sexual release in spite of an over-religious or restrictive environment. While planets within 8th/aspects to 8th house ruler means they intimately collaborated with you in your spiritual transformation in that lifetime, whether you were aware of them or not. With planets in or aspecting 12th house ruler, your succubus/incubus helped you learn how to enlighten yourself through sexual healing and acknowledging past life karma that was dragging you down.
Planets associated with love and sex are Venus (how one loves), Mars (sexuality and passion), Uranus (unique values, LGBT orientations), Neptune (ideals, desperation, craving idyllic intimacy), and Pluto (darker, deeper desires, confronting one's true nature in romance or hookups). So any of these placed in either the 4th, 5th, 7th, 8th, and 12th houses can indicate involvement with a succubus/incubus in past lives and current life.
However, there must be strong natal aspects between any two or more of Venus, Mars, Uranus, Neptune, Pluto, and placed in sexual or occult houses as forementioned. The closer the aspect orb of conjunction, square, opposition, trine, the more important this connection is. Trine between any two or more of the planets, indicates naturally feeling at ease with the succubus/incubus even if they seem unfamiliar to you in your current life. Square and opposition just means you may need time to adjust or get to know them again. How quickly you embrace them depends on how many lifetimes ago you had last shared a commitment.