Use my patent pending "FATTY BE GONE" Seat Divider. It's a piece of thick plastic that looks like it's part of a binder, but it's definitely not that. The patent pending design is thin enough to let you have your entire seat while being large and rigid enough to keep others from spilling into the area under the arm rest. For over the arm rest, you'll need my patent pending "FATTY BE GONE" Multi-Tined Defense Utensil. It looks like a fork, but I can assure you it is definitely not a fork.