Two nudists walk into a therapist's office...
No, it's not the beginning of a bad joke - it's a British ad for Comfort fabric softener (hat tip to AdFreak).
In the spot, a nudist's wife cheats on her husband with another man. But it's a slightly different type of infidelity: the male nudist catches his wife, "sniffing, touching, fully clothed" with another man. "You disgust me," the husband cries.
"But we were only sniffing!" the wife answers. Apparently, Comfort fabric softener can make even nudists love clothing.