Erotic writing isn't necessarily sexually explicit. Writing erotically is often a matter of finding the right words to bring about a passionate charge in your partner. While the line between erotic and pornographic is often blurred and highly subjective, as noted by clinical psychologist Leon F. Seltzer, writing with Psychology Today, the erotic tends to rely more on the use of sensory details. An erotic letter to your partner can be an effective way to entice him all year 'round.
Outline your letter before you begin writing it. Decide what the goal of the letter is. Decide whether your intention is to seduce the person you're writing to or just to express how she makes you feel. Determine the appropriate level of erotic content. This determination can be made based upon how long you've known the person you're writing the letter to and how well you know her viewpoint on suggestive material.
Find an appropriate salutation. Starting your letter off with the person's name is fine, but you may want something a little more romantic. Look for something other than "dear." If you want to use dear, rephrase it to something like, "My dearest Emily," or use a pet name if one has been established in the relationship.
Open the letter with a brief explanation of the purpose of the letter. This is typically because you have been thinking about the person you're writing to and perhaps reliving a night of passion. The opening of the letter may be something such as this: "Our night together is still as fresh as the moment we consummated our love, giving ourselves to one another physically and emotionally. I can still smell your perfume in the air. I can feel the electricity of your touch and feel the silk of your hair . . ." You can vary the introduction to suit your needs, but its purpose should explain what prompted you to write such a letter.
Avoid both pornographic and purple prose. The goal is to use sensory details, such as sight, sound, touch and smell, but to avoid falling into extremes. A pornographic, explicit description of a sex act can be off-putting, but using purple prose (term applied to writing that is overly ornate or flowery) can detract from the erotic nature as well. Using real-world descriptions involving the sensory elements of romance can make your erotic letter more arousing.
Avoid metaphors when describing the sex act. Metaphors are a valid literary device, but in an erotic letter, using metaphors can detract from the erotic and make it seem as if you are afraid of speaking realistically about sex. Also avoid phrases that use the word "like." An example: "The smell of your hair is like a summer breeze." Instead, be direct with a line that reads, "the soft, sweet scent of your hair makes me dizzy with passion."
Write from the heart. Find those things about the person you're writing your erotic letter to that move you. Find the things about the person you're writing to and use those elements to craft an erotic letter that is arousing without being dirty.