I loved the Long March series so I figured out something quite similar to it. I connected five bottle cleaning brushes end to end together and attached them to the middle part of the chains so when poor Holly walked over the prickly bristles they scrubbed and scratched her labias painfully.
Jessica fills her pussy with sharp push pins. First she fists herself to stretch her pussy big enough to insert a see-through cylinder which keeps her vagina open to pour the push pins in. Then she grabs a brush and uses it to keep the pins inside while she pulls the cylinder out. So now the sharp stuff are pushed against her vaginal wall directly. To top it all she fucks herself with a long dildo while the pins are inside and she also uses a vibe on her clit. She moves on the dildo up and down vigorously and she cums pretty quickly. In the end she removes the push pins from her pussy using her fingers.
Nazryana has to stand with her legs open, on tip toes and her hands tied up while she is wearing a rough rope tanga which has 2 kgs and later 5 kgs weights attached to it. This way the rope cuts into her pussy deeper and deeper especially when I swing the weights or when I add my own weight to it. And another bonus for her is some caning and spanking on her butts and tits with a wooden stick and with a riding crop.