It was most likely something called "retrograde ejacualtion", your semen went into your bladder instead of "up and out". This can be caused by certain medicines prescribed for hypertension or for prostate issues. If you are not taking any medicines, consider seeing your Doctor.

(though one night I left my beloved "dry"... by his fourth orgasm in as any hours there was more or less nothing left to come out. He made up for it about two hours later though)

WW

__________________
"I wondered, am I a lesbian, am I straight, or bisexual? Then I realized that I am just a slut.
So where's MY parade?"

---Margaret Cho