What is Rusty Brain?
1.
A sex act, similar to the rusty scupper, where a man and woman are engaging in anal sex because she is having her period. Shortly before climax, she pulls out a strap-on and rubs it all over his face. She then yells "Welcome to the Thunderdome Bitch".
Much to his eventual dismay, Lisa pulled a rusty brain on her boyfriend while she was having her period.
See