I too had a pencil dropper....hypotonia so he gripped his pencil tight...then the muscles would fatigue and he would loosen his grip and the pencil fell. We solved this problem by having a cup full of pencils (he had an oversized desk) on his desk and if it dropped he left it and pulled out a new one from the cup. At lunch time he collected the 15 or so pencils from the floor and started over.
We were also homeschooling when this was an issue at seven years old so I didn't care if the floor was littered with pencils... But I do know how exasperating it is every time a pencil drops...he is almost 14 now and he drops his pencil once in a while not constantly. OT and sports (gymnastics and swimming) really helped.
