Urinary retention caused by old semen in prostate?

I'm a 40 year old male. Have been having urinary retention problem for the last 4 or 5 years.

I recently saw a urologist. He performed a prostate exam and ruled out enlarged prostate. Urine test showed no UTI. The urologist then talked to another (likely more senior) urologist. The 2nd urologist came into the room and pressed on my prostate *really really* hard with his finger. Some semen oozed out.

He told me that was old semen accumulated in my prostate and it caused my urinary retention. He said the only way to get better is to make sure I ejaculate every time I get excited.

1) I have never heard of this condition. I tried to look up more info but came up empty. Can anyone point me to any info on it? Is there a medical term for it?

2) I always ejaculate when I have sex, so why do I still suffer from this? I do usually take a long time to climax (30 min - 1 hr), is that what caused the problem? Should I make sure I ejaculate within a certain time limit? What is a "safe" time limit to aim for?

3) Is there any thing else I can do? Any way I can do the "press the prostate" procedure on myself?