Yes, transmission takes place inside.
You can dump a bucket of seman on you it will not result in transmission.
how does hiv transmission happen thru the urethra then? Only when the penis is inside the vagina/anus?
So it's safe for me to come into contact with potentially hiv-positive semen as long as it's outside the body?
Yes that is true, but HIV is fragile so once outside of the body it is deactivaed for several reasons.
sorry, im a bit confused. I thought getting foreign bodily fluids in the urethra was a primary means of transmission for males?
Your thinking are not facts and the fact is as you have been advised, HIV does not stay active outside its host and is unable to infect.
ok, thanks. im still worried because it was only a duration of a few seconds from the point that he ejaculated and i had it on my penis (and possibly in my urethra), and i don't think hiv 'dies' that quickly outside of the body
HIV does not 'survive' outside the body. You had no risk.
is it not a risk if his semen came in contact with my penis? can't it get in through the urethra that way?
HIV is not transmitted by masturbation.