When a party or other social event becomes overrun by bros. Bros are males who often wear sandals, cargo shorts with a plaid pattern on them and visors/hats with prefrayed brims. You will know when you witness an exbrosion because whatever you are doing will be ruined by their obnoxious nature.
The party sucked after the exbrosion, everyone was turned off by their terrible out fits and how obnoxious they were. they were such bros it wasnt even funny
by The master bro December 08, 2009