When a bro says repeats "bro" several times in a serious tone to convey the gravity and significance of a prior statement. All subsequent "bro"s after the first should be spoken in a lower tone, leading to a series of "bros" that gradually get lower like a limbo.
Bro 1: so I totally fell asleep instead of having sex with her. She was so pissed.
Bro 2: Bro
Bro 1: I was really tired!
Bro 2:... bro (lower)
Bro 1: do you think she'll ever sleep with me again?
Bro 2:....bro (even lower)
Bro: don't do the bro limbo to me, bro