My theory is that pitpussy has become such a prevalent fetish thing now for artists because it allows them to draw something with basically all the traits of a pussy without worrying about censorship. Warm, wet, soft, pink and the crease(s) in the middle are like the slit, to varying degrees.
This doujin page as an example, the pit fucking portion in the bottom right looks outright like a vaginal xray.
https://files.catbox.moe/x32mca.jpgAnyway, luv me pitpusy
luv me feet
luv me sweat
luv me steam
simple as