The unintentional but unavoidable girth/tightening in a heterosexual male's pants due to the witnessing of another male's unbelievable stunts and/or acts.
Most common triggers to cause an unavoidable broner include but are not limited to, are: Chuck Noris, Jason Statham, Arnold, The show 'Cops', Showcase Action.
To calm a broner down, one must immediately watch 10 mins of any of the Twilight movies. Or listen to something by Lady Gaga. Actually, any attention to something that resembles a male covered in glitter, and lots of make up should do the trick.
I totally got a broner after watching 'The Expendables' tonight