Reading Books about Sexuality
1-11-2003 | IslamWeb
Question:
I just wanted to ask if it is not Haram to read books that describe sexual manoeuvres for the married persons without any pictures?
Answer:
All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad 
is His slave and Messenger.
If you are referring in your question to the books that explain sexuality, those books that explain the methods of the meeting (encountering) of a man and a woman unlawfully, then these books should not be read even if they contain something permissible because the predominant side is that they are not permissible.
These books encourage adultery and mischief, and they arouse and excite desires. If they contain naked pictures of men and women, then they become absolutely forbidden. Because looking at the 'Awrah (parts of the body that must be covered in Islam) is absolutely forbidden in the Book of Allah, as Allah Says (what means): {Tell the believing men to lower their gaze (from looking at forbidden things) and protect their private parts (from illegal sexual acts). That is purer for them. Verily, Allah is All-Aware of what they do.} [Quran 24:30]
There is no need for a person to read such books, because the encounter of spouses is a natural matter that everybody knows by his own natural disposition without the need of being taught about this.
And if you are referring (in your question) to the books which teach the etiquettes of relationship between a husband and a wife according to the Book of Allah and the Sunnah (guidance) of the Prophet and the saying of our righteous predecessors, then this is permissible. It is part of the religion and that is why Islam has given it its proper importance. Allah Says (what means): {…and live with them honorably.} [Quran 4:19]
Living with them honorably is a general term that includes all aspects of relationship with one's wife, including sexual intercourse.
It is reported in the Sunnah (the way and guidance of the Prophet) that the Prophet ordered us to treat our wives amiably and playfully (pleasantly).
Imam Muslim narrated from Jaabir 
who married a previously married woman; therefore, the Prophet told him: “Why did you not marry a young girl whom you would play with and she would play with you.” Another narration reads: “…Whom you would make fun with and she would make fun with you.”; and so forth.
We find the proof of this in the biography of the Prophet with his wives. He used to kiss his wives while he was fasting, and used to drink water exactly from the point where ‘Aa’ishah 
had drunk from while she was in menstruation, and many other etiquettes (from his guidance).
The scholars point out the importance of sticking to these etiquettes. Among them ImamAl-Ghazaali 
who mentioned in Ihyaa' ‘Uloom ad-Deen: “When a husband fulfils his desire, he should not hasten to withdraw until she fulfils her burning desire as well. Perhaps she would not fulfil her desire (ejaculate) quickly as her husband, and she will become greatly excited. Therefore, when he withdraws, this causes her harm. The difference in ejaculating causes mutual repulsion no matter how soon or late the husband precedes her in ejaculating. When they fulfil their desire (ejaculate) at the same time; that brings her more lust and pleasure. This allows the husband to be more active (last more in the process) with her, as she would probably be ashamed (to ask for more).”
He should at least have sexual intercourse with her once in every four nights, this is what is just. We are allowed to have four wives, so it is for this reason that we could delay having intercourse up to four days.
Therefore, it is permissible to read this kind of texts, because this clarifies how to fulfil the rights of one's wife (and meet her desires) in a lawful way. There is no difference whatsoever between what the scholars have written and other physicians and psychiatrists as long as they do not go beyond the boundaries of religion.
Allah knows best.