Not necessarily. I was in a porn theater one time and had pre-lubed my ass, with frozen crisco so not quite so obvious that my ass was full of grease. Having no luck, I begged this hot bearded Daddy to fuck me. He wanted to use a rubber because he didn't want to catch anything. I let him fuck me in a dark hallway with some guys watching.
Well, the grease in my ass broke that sucker down, but I didn't feel anything but his cock pistoning. Once he put it in, he didn't pull out. When he pulled out, my ass was full and dripping with his load. He was like "Oh the rubber broke" and looked kinda guilty as he pulled up his pants and split.
Dude must have felt it. Maybe it broke while he was shooting? I felt nothing, but boy did I grin when he told me I got the load I wanted. Anyhow, I stuck a couple fingers in to feel all that fresh stranger cum in my ass to pull out the piece of rubber that was still up my fuckhole.