A girl who dyes her hair so red that while having sex the sweat from her forehead blends in with her hair dye, causing the sweat to become red and resemble period blood.
Bard: Last night was crazy. My bed looks like someone was murdered on it.
Derek: Seriously?! What happened, bro?!
Bard: I was having sex with my girlfriend. Right before she dyed her hair red. Need I say more?
Derek: Goddamn Ruby Red Period Heads.