For some reason, when I have sex, I have trouble concentrating on what i'm doing. Sometimes i'll be worried that I won't keep my boner, and then it will be gone. Usually i'm worried about cumming too fast, but for some reason last night I went for 25 minutes and still couldn't cum --- and ended the session without getting off. I know that the whole reason this happens is because i'm not focusing on the girl and staying horny....but i'm not sure what to do about it. Can anyone give me some insight on this?