Our turn to bring the snack but didn’t manage to buy oranges until the last minute (in spite of the fact that the date has been known for months).  Fortunately, orchard next to the fields sells 10 pound bags for $3 so I brought knife and cutting board along with me.   Bought oranges then saw M. and B. loading their things into the car.  Felt very  parenting-inadequate, as usual.  Hid behind orange trees until they left.  Cut oranges in car while standing on the side of the road, taking care not to drop any sections on to the dirty car floor.  Filled bowl.  Voila.