it is true that during the meditations these thoughts are known or treated adverse. it is also true that  after ejaculation some one  or mostly feel loss of energy, fatigue and some some shyness. some one realizes that they feel activeness. it is a bitter experiences about sex we do and ejaculate losses our key products of the body and feels that i am getting enjoyment. who can get enjoyment after loosing some is true that the sex is the very concealed and inner instincts of the individual. wants, does and after that he feels varies person to person and it is individualistic approach. but  after a certain ages you want to be act sex but your body does not help you. mind is active but body is not fulfilling your desires. although it is a secretion of the hormones. but it is the foundation of the strength of the body. if you will preserve it , it enhances longevity and your aura. sex desires must be limited. during newly married life one can entertain more but after the certain ages you also feel to keep away from sex. i think it is a mental desire, physical wants, emotional satisfaction and in the end it is a totally lost of time, money, energy and has a few minutes job but we are mentally attached with the sex called  sexuality.