Hey, glad you like it!
Those fetishes already exist in game! You can get a Footjob from Aria and it gives the Footworship fetish. That scene is a bit hard to trigger though. You had to had sex with her before than there is a chance that a pair of panties will appear in the laundry basket in her bathroom each day, if you try to steal them she will punish you with a footjob.
BDSM (Sub) also exists, you can gain it by losing to Mimics in the Opal Grotto. They tie you up in chains and ride your face or your cock in their chest. This can sometimes lead to a gameover though.