The freckle right beside someone's left eye for example, it'd take about three or so days of being in love.
The slight pointiness of their side teeth, a week.
The way they bite their cookie down instead of through, give or take two months.
It's like clockwork.
Almost like a requirement, really - the acute awareness people suddenly get when they enter that stage of questioning whether they're just bored or really in love.
And I'd like to think it's the same for me, but that's clearly not the case.
Not when I'm looking at her at this very moment, watching her lick the bastard's blood off her arm, her pinkie stained from a different kind of red.
"Third one this week. Oh, joy," says our friend.
Or, acquaintance, really.
Stranger we hang out with.
"You could at least pretend you think this is worth something," the girl I love says, straightening her rumpled skirt. I can't help noticing her finger blend with the fresh liquid on her uniform.
Our friend doesn't even answer back. She just stands from the wall she's leaning on and walks off, blood stains and all.
My love turns to me and wipes her mouth, and I can't help it anymore.
"That's not allowed, you know," I say, eyes very pointedly staring at the stain on her smallest finger the same way it always has ever since we got rid of the first body.
"Of all the rules I broke in this place," she replies, red lips quirking into a smirk, "that's what you're most concerned with? The fact that I wear lipstick?"
"We," I tell her. "Rules WE broke." I can feel my own smile growing on my face, completely disobedient to the things my brain is yelling. That always seems to be the case when I'm with her.
"You can't write me off that easily yet."
She walks towards me, her arm reaching out, and slithers her pinkie finger around mine.
There's moonlight bathing my skin from the window high up the wall, casting an eerie glow on the body lying on the floor not too far from us.
"Ever," she says, smile wicked and unashamed. "I can't write you off easily ever."
When she pulls me closer and leans to kiss me, we find ourselves back in the darkness where the moonlight can't reach - pinkies still intertwined, one stained red and one religiously spotless.
And all I taste is blood.