It is very difficult to name just a few possible interpretations for this dream.
It is complex and complicated, and the interpretations vary with each dreamer and with the situations in the dream.
A sexual dream may be about physical pleasure but it may also be about power, control, manipulation, virility, and effectiveness.
It may be a form of wish-fulfillment or a memory.
In most cases it is not a prediction of things to come in the near future. Freud believed that experiencing sexual pleasure in your dreams is always desire or wish-fulfillment.
If you are watching other people having sex it may be a reflection on your emotional and mental concerns about sexual performance or interaction.
The meaning depends on your emotional reactions to what is going on and on the general mood in the dream.