Rub the orange wedge along the rims of 2 pint-size glasses. Pour the sugar onto a shallow dish and dip the rims of the glasses into the sugar.
Put 2 to 3 scoops of coconut sorbet into each glass. Fill each glass with orange soda (you may not need to use it all). If you pour the soda over the back of a spoon into the glasses, it will keep the soda from breaking up the sorbet too much. Top each float with lots of whipped cream and sprinkle with yellow sanding sugar. Add a straw and enjoy!