I'm in my early 20's and I have a wonderful girl. the problem is my penis does not stay hard. you know when it's stand there for a long time. I feel it get hard when it touch my girl body or get an erection. Sometimes in the middle of our sex it turns soft eventhough i'm really enjoying the moment. can you guys tell me if it's okay or not? I'm having sex twice a day and sometimes once daily..I was masturbating a lott before. should i go to a doctor or it's fine?