It depends on wheteher you want to have sex in a lucid dream. Motivation is main factor in attaining lucidity, so if your goal is to have sex in the lucid dream = the more you are horny, the bigger is your motivation and therefore better chance to go lucid. I used this horny-motivation with my wild atempts and it was one of the few wild/deild methods that have worked for me. Sex/masturbation alone does not have impact on lucid dreaming frequency.