You don't actually need a pastry bag to pipe these, but it sure makes things handy. This mixture is too thick to pipe from a plastic bag (the usual go-to pastry bag alternative) so make your own with a triangle of parchment paper instead. Here's a great video on how to do just that.
'ice cream topping' on Serious Eats
Bright, citrusy oranges and mellow, nutty caramel have a natural affinity. Toss in some toasted pine nuts and you've got a seriously delicious dessert sauce. Try it over polenta cake or vanilla ice cream. It will keep for at least a week in the fridge. Reheat it over low heat before serving.