On especially hot days in Cebu, my mother used to break out the old-school Osterizer and make my brother and I avocado or papaya shakes, depending on the season. My brother and I used to make avocado or papaya "mustaches" with the shakes, gleefully licking our upper lips clean to make another green or orange mustache.
In my own kitchen 20 years later, my son makes the same mustaches, though he does it inadvertently. It never fails: Jonathan will slurp from a straw at first, decide that he can't deal with plastic interface, and eventually sips directly from the cup, pinkies up.
2 (5 oz.) cans of evaporated milk
1 very ripe avocado
A dozen ice cubes - or however much fits in a standard ice tray
2 tbsp. sugar (more or less to your taste)
Dump the ice first into the blender, then follow with the rest of the ingredients. You'll know the avocado is ripe when you can easily scoop out the green "meat" with a spoon and you're left with a clean shell. I usually add very little sugar at first, then add more according to my taste. The shake should be very creamy, but not so thick that you can't drink it through a straw. You can also use evaporated milk with a lower fat content, but the shake won't be as rich.