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2.
When your best friend takes off his condom and turns it inside out for you to use.
My roommate knocked on my door and asked if I had an extra dong bag, I said regetably I was still wearing my last soldier. But as a good mate, I turned that shit inside out and saved the day with a Brophylactic!
by 73Fatty September 14, 2012
 
1.
When one bro prevents another bro from obtaining sexual goals. Primarly happens between college roomates.
Dude you better find some other room to sleep in. Dont be a brophylactic.
by Steve the Palm Tree September 04, 2009