Dreaming about something obscene indicates your thoughts are leaning towards the sex and the sensual experiences at most of your waking hours. Your desires to express yourself sexually are restricted by the fact that you have to work, see friends and family. Instead you did rather spend time with your significant other in the warmth of each other’s embrace.
Also, the obscenity in a dream signifies that it is perfectly acceptable to envision people naked as it is part of human nature to procreated.