The "smile" is a favorite response of horse owners and can commonly be seen after a horse taste a new or odd tasting item such as peppermints. The reaction of the horse and the oddity that creates the flehmen response has been a great source of amusement for people of young or old. Many people have also worked to train their horses to elicit this response when given a cue. This can be done by instituting a strong tasting flavor and continual reinforcement when the desired behavior presents itself. The following video shows the step by step training process:
Through our riding program at my university, we have a very special horse name Aegis. This lovable horse was trained by his previous owners to "smile" and "give kisses" on command. It is a great form of amusement to us college kids. Whenever I just need a little love from the horses I can go out to his field with some grain and as soon as he sees the grain in your hand he knows. All you have to do is point one finger in the air and he smiles to the world!!!! He will also lick your cheek if you point to it. This has showed me how talented and versatile the horse species really is.