What distraction is enough to stop having sex?

Maybe if someone comes over unexpectedly or kids walk in or ask for help

Noise always alerts me.

I don't have kiddos yet, but I can imagine that would stop me for sure.

we've got a good amount of privacy in our room, we keep the cat out and we don't have kids so most of these don't apply to us. Frustration though, that's the instant and ultimate killer (for me at least), more than pain, more than noise or pretty much anything else.

With perpetration and good timing, usually nothing stops us except a sick child.

A knock on the door or a strange noise would be about it.