Bed sniffer is someone who actively tries to get into other people's sex lives uninvited and when it is not their business. a bed sniffer is also when someone is on the act of persecuting people based on sexuality, non life threatening, and sanitary fetishes and kinks.
1. george: "Did you really tell the head of our department that Jack was having sexual relations with a customer that actually met at a cafe??"
Jake: "of course I did, they were both men."
George: "Jake, you are just being a bed sniffer, the two did nothing wrong but shared coffee and went behind closed doors."
2. Blake: "Father Daniel what are you doing?"
Father Daniel: "I just got a collection of evidence for sinful sexual activities between Irene and Matthew."
Blake: "for what??? why would you be creepy like that?? their kinks have nothing to do with you.
Father Daniel: "it does because its just missionary and proper, soon the whole town will know of this evil and corruption"
Blake: "you are going too far bed sniffer!"