How to make an orange last all day

I remember as a young 'un that my mum used to put an orange in my Xmas stocking. That meant it must have been a treat. (Probably during her younger years. oranges were things of rarity,  because of the war no doubt.) 
Anyway, cut an orange into wedges, fill the glass with water and the wedges, and enjoy. Just keep refilling the glass with water. 
And this is the genius part,  before bedtime, eat the orange. It's bloody brilliant! 

Ah well. Until tomorrow...