Avocado shakes are a childhood favorite of mine. I've been making these since I was a kid, so I don't measure this recipe. Just don't put too much condensed milk or sugar. You can always add them in later if it's not sweet enough.
Avocado (1 avocado = 1 glass)
Condensed Milk (I use the Longevity Brand)
Sugar (depending on how sweet you want it - I don't use much)
Blend it up
Taste to make sure it's to your liking. You can add more sugar to make it sweeter if you like.