Sophie Rain is already bored going back and forth with Lil Tay ... as she tells us, it's nothing but "fake drama" from someone who’s been irrelevant since middle school!!!
"Lil Tay’s been falling off for years, now she’s making up fake drama just to stay relevant," Sophie tells TMZ ... "It's giving desperation. If you have to invent beef to get views, maybe it’s time to log off."
ICYMI -- Lil Tay upped the ante and challenged Sophie to a $60 million boxing match .