Sex is one area where surprises are generally a very bad idea. Many relationships have ended because one partner thought the other would enjoy x, only to find out that they were disgusted/insulted/traumatized/etc instead. It is difficult and may be impossible to recover from this type of oops.
The best idea is to set aside some relaxed time to discuss interests, curiosities and hard limits with your partner. Probably start with the hard limits so you don't stomp all over them with your interests. Then decide to try out one thing you both are interested in. Keep communication open at all times. Go slow. Keep in mind that some (many) people have been sexually assaulted or abused in some way and that will make them incredibly sensitive to anything that recalls those feelings.
You want this relationship to be as enjoyable as possible for as long as possible? Yes? Don't take chances, be smart, be kind, communicate openly and good things will happen. I promise.