Rusty Tailpipe

The sexual act of inserting ones menstrual blood covered member into their partners anal cavity

Bro1: Dude, I totally gave your sister a hard rusty tailpipe
Bro2: Damn dude, I knew she was a whore, but wow
Bro1: Yeah man, she was totally into it
Bro2: Dude, you might have AIDS, just saying.