Some helpful tips to decipher Greer's tail movements! I do try to set the mood / vibe when the tail is mentioned in-threads, but this is a clearer list for those who might want to add some into their own replies / meme responses!
STRAIGHT UP / ERECT, FUR FLAT: you've grabbed her attention, & she's very curious about you (or what you have in your hands)
STRAIGHT UP OR OUT, FUR PUFFED UP: she's scared, back up or else she'll pounce!
TIP OF TAIL QUIVERING: she's very happy to see you, you make her very happy!
TIP OF TAIL FLICKING BACK & FORTH: feeling playful or cheeky. she might start flirting with you! alternatively, she's laser focused.
TIP OF TAIL TWITCHING / JERKING: what's the god-awful sound? it's grating on her ears! make it stop!
TAIL SWISHING WIDE LAZILY / SLOWLY: content & comfortable, but still on alert. alternatively, it's moving to help keep her balanced in a crouch, on a ledge, up high, etc.
WHIPPING BACK & FORTH QUICKLY: you've pissed her off! or excited her. either way, you'll find out soon.
TAIL HANGING LOW & CLOSE: she's apprehensive!
TAIL BETWEEN HER LEGS / WRAPPED AROUND HER LEG: terrified & trying to hide.