You do realize that when your pregnant, you still have your period after you have the baby right?
Im a girl, and really, periods aren't THAT gross, it's just blood, not even bad. Periods are a good thing!
Girls don't typically have sex on their period.
But if you do, yes, chances are you might get blood on your wang.
But girls only blood on intervals, like every 2 hours they bleed a little, then they don't bleed again for another 2 hours. So you could have sex during those intervals and BAM, no blood.