(Of a male) The act of not pulling out of a female's vagina when about to ejaculate; made worse by the non-usage of a condom.

This phrase is the opposite of the popular "Pull out before it feels good", and instead means to go past the point of no return (i.e. a creampie)

This may further result in pregnancy or a bag baby.
I was getting it in with my girl this weekend, when I decided to cross the rubicum. If she wasn't on the pill, I'd be a father for sure.

I accidentally crossed the rubicum with my friend's sister the other day. Thank goodness for Plan B!
by GerYard April 09, 2014

Free Daily Email

Type your email address below to get our free Urban Word of the Day every morning!

Emails are sent from daily@urbandictionary.com. We'll never spam you.