Sex with a friend
"Remember that dreams are symbolic and not literal," Kelly says. "Did you recently have a fight with this family member or friend? Joining with him or her in your dream could be symbolic of reconciliation, empathy, or merging with and understanding their point of view or the qualities they represent."
Sex with a friend's S.O.
"In dreams you can explore secret attractions without having to act on them and face the consequences of those actions in the waking world," Kelly says. "Remember, when you see this person and blush crimson, you have nothing to be ashamed of."
And while having a dream with your friend's significant other can be hot, it's probably best to keep that one to yourself.
Sex with someone of a gender you do not normally have sex with
Sex with varying genders can mean different things depending on what your sexual proclivities are and where you are in your life.