Summarize:

Nude art models are typically expected to strike four basic poses during their sessions.   These are standing, seated, reclining, and semi-reclining or prone. The standing pose requires you to stand in a variety of ways with your arms, legs, hands, and feet engaged in various ways. You might have props to hold or have to hold a particular facial expression. The reclining pose will typically require you to lie down on your back on a sofa or couch in a comfortable position. The semi-reclining pose will require you to lie down on your stomach while lifting your chest, as you would do to read a magazine at the beach. These are the four basic poses, but there is a variety of movements and gestures that you can make when you hold them. It is important to note that when in a standing pose, not to let your knees lockout (doing so may cause you to pass out). Draw on any personal experience to think of poses that are interesting or inspiring. Any physical activity may be a source of good poses.  A good model must be able to be expressive from the bottoms of their feet to the tips of their fingers. Art is dynamic and your poses should be as well!   Many models are inspired by the poses depicted in classical works of art. Yoga poses are often used because they engage the muscles in interesting and dynamic ways. Different kinds of poses can be held for short or long periods. It is best to be prepared to hold still for a long time.   The time required for a pose can be described by any of the following three terms: gestures, short poses, and long poses. Gestures are poses lasting less than three minutes. Short poses last three to twenty minutes, and long poses which are held in multiple 20 minute intervals with a short break in between. The latter is generally the norm for painting and sculpture; drawing classes will require a number of shorter poses. Any class may begin with a few gestures as a "warm-up". If you're in the middle of a long pose and need to move, someone will use tape to mark the position of your body. Just ask, "Can someone please tape me?" " You should come prepared to your modeling session so you don't need to trouble the artist by asking for anything and maintain your professionalism.  The most important thing you need to bring is a robe so you can wear it between poses or to use the bathroom. You should also bring a towel or blanket to sit on for hygienic reasons. Bring slippers or sandals to slip in and out of quickly on breaks. You might also want to have water or snacks with you. Always bring a date book and pen (or your phone) for booking future sessions. You will want to be clean and look natural.   Before you leave for your session, shower and apply lotion to soothe dry skin, which could cause you discomfort while posing. Wear minimal jewelry unless otherwise requested. You shouldn't put in a ton of hairspray or wear make up unless requested. You should look as natural as possible.
Prepare your poses. Be expressive. Be prepared to hold each pose for a specified amount of time. Put together a "modeling bag. Prepare your body.