Well I don't think it's sexual energy that builds up, it's rather overall energetic state of your body that keeps growing. Better compare it to the phone with the battery nearly always at the emergency and with limited functions available. So that when power takes you up from emergency threshold and your dormant functions start becoming active you sort of freak out and your brain is trying to convince you that it's sexual energy that is growing together with certain solutions on how to use it to keep the status quo for if it will keep growing ramifications can be life altering. And we as people usually afraid of changes due to mostly negative thinking and expectations (I think it would be true to state that most of us were brought up with attitude of looking at life whilst simultaneously trying to find and see everything that might go wrong, that might cause harm and take some action out of fear of the imaginary problems instead of see what positive changes it could bring... Yes, I had experienced that. Did you feel a slight chaser effect afterwards? Basically speaking it's our, still ingrained, attitude towards women that plays out in these dreams. Take a note on how you think and feel about women when you go about your everyday business for it will reflect itself in your dreams.