The act of fraudulently using a restroom stall to sleep (typically at work when a nap is badly needed) rather than for it's intended purpose. Usually accomplished by normal sitting posture on the toilet seat, with or without a paper cover. Particular toilet designs are more suited for shapping - those with a flip-up top seat can provide a comfortable, inclined backrest, while those with traditional "commercial" plumbing flush handles can be quite uncomfortable to lounge against. It this last case, the shapper may choose to lean to the side, bracing themselves against the wall, or even lean forward, elbows on knees, although this increases the risk of shap-drool puddle formation on the floor.
"He was in there forever! Must've had something bad to each for lunch"
"No - he wasn't taking a shit - he was taking a nap."
"Oh...you mean a Shap."