Sex With an Ex
If you find yourself dreaming about an ex-partner, it could be a sign you are not entirely over the break-up. If the split has only happened recently, then this sort of dream is probably not a concern. However, if you have been apart for a while, and especially if you are with somebody new, then there could be a problem there. Taking time to listen to your thoughts, and understand your feelings towards the ex, can go a long way to resolve any issues. Be honest with yourself, and try to find closure in anything that crops up.

Sex With an Authority Figure
Dreaming about sex with an authority figure usually has the same underlying cause; you are seeking approval from somebody in your life. This approval does not have to be sex-related or associated with the person in the dream. The link is likely to be with a parent, teacher, or boss that you hold in high regard, but feel that you have let down. If this dream is a regular occurrence, it can help to take time to think of past relationships to see if you feel under-appreciated in any way.
Oral Sex
There are usually two aspects to dreams about oral sex, depending on whether it is something you partake in or not. If you do, then these dreams are generally nothing more than your brain having a bit of fun! However, if you are averse to oral sex, but still dream about it, it could be a sign that you are challenging how you think about things. It may not necessarily be to do with sex either. It could be anything from relationship problems, to your career path, through to your religious beliefs! It is common for people to think they know what they want, only to find that later on in life, they were mistaken in these views.
Fetishes or BDSM

Dreaming about particular fetishes or bondage is quite normal even for those who do not participate in these activities. It is most commonly a sign that you like to be in control of a situation, or you like being controlled, depending on your role within the dream. Inherently, there is nothing unnatural about this, and it is not usually a sign of anything more profound.
Everybody will dream about sex from time to time. Still, if there is a recurring theme and it happens regularly, then it may mean you need to look deeper into your thoughts. It is important to remember that there is nothing wrong or abnormal about any dreams, as it is just the way your subconscious plays out specific ideas. However, by understanding a little more about them, you can make progress in your everyday life and improve your relationships with your friends and partner.