When doing a girl from the back, wait until you're getting ready to "take care of business." Then reach around her face, making pinchers with your pointer finger and thumb. Accompany that with an "nigh nigh nigh" self-made lobster sound. Then when she turns around like "What the fuck" you "take care of business" all over her.
Juvenile 1: "Last night I was with my girl and I pulled the Lobster Felix on her"
Juvenile 2: "Jeah Booooyyyyyyy!"