Short answer
Islam permits intimacy between husband and wife within marriage while placing certain boundaries on sexual conduct. The couple should learn these boundaries and respect them.
Islamic Guidance
What Islam teaches
Islam permits lawful intimacy between spouses but prohibits certain practices. The Qur'an discusses marital intimacy, and authentic hadith provide further guidance concerning prohibited forms of intercourse.
Practical Guidance
What you can consider
A married couple should learn the basic Islamic rulings concerning intimacy from reliable scholars and maintain privacy, mutual respect and consideration in their marital relationship.
Sources
Qur'an 2:222-223; Sahih Muslim, Book of Marriage.