Your cycle feed?

Naomi • •° It's always Halloween here °• Cryprid/Victorian/Fae/Occult/Spooky Shit lover •° Gamer by Nature °• Meme Queen Supreme •° ♡AFK Arena is life♡ °• Nara is my WIFE °•
Hiii! I just have a quick question:
The little plus in the center of your hot keys for the app... Is that to use use for when you have sex? Or when you're on your period. I don't really know when to use it, especially since I don't have sex when I'm on my period. So I've been basically using it the days I've had sex. And I really feel like I'm using it wrong.