I get frequent erections when I sit during day, generally after lunch or any meal of the day. I also get erections during sleep. I masturbate slowly and in a controlled way to release the sexual tension. I also walk for 10 to 15 minutes after slow masturbation to feel light and relaxed, but I never ejaculate as ejaculation makes me feel weak and drained. Will this be harmful to my health ( physical or sexual ) in any way in the long period if I don't ejaculate? Please guide.