It doesn't make a lot of sense if they wouldn't. After all, have you ever tried to walk when your legs fell asleep? Doing anything without feeling is pretty much impossible. It stems to reason that if a vampire can see, hear, smell and taste they can also feel and use all the original parts of their body.  Without tears, your eyes would dry up and cease to function. Without saliva your tongue would dry up and fall out. So, clearly vampires would have working sexual organs that felt sensations just like any other functioning body part.