Being related to somebody because you've both had sex with the same person. Related through the pelvic bone.
Timothy: I had sex with Jordan last night!
Kieron: Cool, I had sex with her last week, that makes us pelvic brothers!
Kieron: Cool, I had sex with her last week, that makes us pelvic brothers!
by HunStarRaw March 18, 2011
Get the Pelvic brother mug.