Characters
Dogs are idiots. Think about it, Smithers. If I came into your house and started sniffing at your crotch and slobbering all over your face, what would you say?
— Burns · The Simpsons

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker asks Smithers to imagine the speaker behaving like a dog in Smithers’s home. Sniffing and slobbering would seem offensive from a person, so the comparison is offered as proof that dogs are foolish. The joke applies human social expectations to ordinary canine behaviour.
Context reviewed