A fork of Rural Dictionary
When two men have seen each others penises,
"Me and Mark are Jungle Brothers now" "How come?" "I saw his penis so I pulled my pants down so he saw my penis too"
When two men have contacted the same STD from the same sexual partner.
“Yo, I heard you banged Adrian.” “Yea, what about it?” “She has Herpes, dude. We’re jungle brothers!”