Monty usually doesn't party much. It seems that Rogers time with Mimie has brought Monty into contact with Mimie's brother Micah, who dragged him out for some partying. Body Shots are the treat of the evening, and it seems Monty recognizes the marshmallow colored mare he's about to enjoy one off of. That or he's just not used to such shenanigans...maybe both actually.

Micah and the art came from askmimie.tumblr.com
Rarity belongs to Hasbro
And Monty is mine