Stealthing is barebacking someone by deception. It involves either removing the condom whilst keeping the bottom unawares or tampering with the condom so it breaks again with the bottom not knowing that the condom has broken. Every video I've seen on Xtube has a disclaimer that the bottom was aware and consenting to a bareback fuck.
I've spoken with a couple of guys on Grindr who admitted to stealth anonymous guys in real life. Bizarre.
Porn wise, I am grossed out by pain, blood and scat.