Honey Boo Boo's Sister Pumpkin Goes Hardcore on OnlyFans

Pumpkin is diving into hardcore sex on her OnlyFans account ... and Honey Boo Boo's sister tells TMZ there's enough dessert for seconds and thirds.

Here's the deal ... Pumpkin -- real name Lauryn Efird -- joined the adult content platform in March ... and, at the time, she said she would start with some naughty nudes before going to pound town ... and that day has finally arrived.

Pumpkin tells TMZ ... "I really started doing hardcore because, truthfully, it's another revenue of money and so many options to do and give."

In one video for sale on her OF, Pumpkin is smashing her boyfriend, Darrin Kitchens.

The video has been available as an additional high-dollar purchase for subscribers -- and it's exactly what you'd imagine ... they're banging on a bed in front of a camera.

Pumpkin tells us ... the hardcore post costs $100-$150, depending on how much footage is requested.

And yes, there's going to be plenty more slices where that came from ... Pumpkin tells TMZ she has some girl-on-girl content planned ... which may turn into a threesome with Darrin down the road.

As we reported ... Pumpkin told us after she launched her OnlyFans that she was already raking in the dough ... and she's even taken her newfound talents to the strip club.