When a bro does and or has something epic; a sick shot, raging flow, huge hit, snipe, death check, home run check... you should get the point.
mainly to do with lax but it can also be used in some sports... except baseball.
Brogasm is normally used as Brogasmic in present tense
"Dude that behind the back no look shot 20 yrds out was Brogasmic"
"His flow is brogasmic"
"His tilt is brogasmic"
"A Pro7 with tilt, backward 7's is brogasmic"
"He just got wrecked."
"I know that was brogasmic"