A staple in so many BDSM porn scene, face slapping is a visceral expression of power and control. It’s also considered edge play because there are many risks involved in hitting the face. So you need to make sure you know what you’re doing before face slapping someone or letting someone slap you.
It’s an activity that can be used as punishment or as part of sexual activity, especially oral sex. It can be used to emphasise the power exchange between Dominant and submissive. As there is a strong psychological effect with face slapping after care is incredibly important when it’s employed.
Fetishes are often about transgressing social convention and playing around with taboos. One of the things we as a society have developed some serious taboos regarding is, unfortunately, our own bodies - particularly the bits of them that grow hair and make smells! Naturally, then, there are some people for whom the idea of armpit licking, sniffing or even armpit sex is erotic and fantastical. It might not be the most common of fetishes, but it's an entirely healthy and explicable one! Some of those people will prefer their partner's armpits to be unshaved and/or unwashed, while others are more a fan of smooth and sweet; whatever you're into, talk it over with your partner to find out if they'd be happy to help you indulge this particular fantasy.
Foot fetishes are actually very common, and are amongst the most frequently mentioned fetishes in popular media. The feet are a body part sometimes associated with smell and unattractiveness, which gets some people's taboo centres working. They're also erogenous zones for many, particularly as most people aren't that used to having them touched. Boots, heels and other footwear are precisely the kind of sexualised accessories so many people fall for, meaning that the feet inside them can also end up as the object of someone's desire. There are tonnes of feet videos and feet pictures online for those who can't get enough of pretty feet.
If you have a foot fetish, you might find that you're especially drawn to a certain kind of foot: large feet, small feet, ones in see-through shoes or bare feet.