When one is in the 69 position and the first party discovers that the second party is menstruating, the first party becomes alarmed and jerks, forcing either their phallus and/or pubic mound into the second parties' nose/mouth; thereby causing a nosebleed/bloody lip.
You ever try a Heinz 69? Quite enjoyable once you get past the fact of what is really happening...but a man always knows he's gotta finish.
Two lesbains going down on each other while both are on the rag
The heinz 69 is outlawed in all 50 states yet many women still practice this incredible sexual act.