Mix together the sweetened condensed milk, yogurt, water, and lime juice and pour into your popsicle mold. Cover and freeze for about 1 hour so they are just beginning to set, then insert the popsicle sticks (this will ensure popsicle sticks stick straight into the pops, rather than floating at an angle). Freeze until firm - I like to let these set at least 8 hours if you can wait that long.
Finely crush graham crackers (I find that the trusty ziploc bag and rolling pin method works great for this), and pour into a shallow dish.
Remove popsicle mold from freezer and run hot water over the bottom of the molds for 20-30 seconds to loosen pops. Remove pops from molds and roll in crushed graham crackers to coat. Popsicles can be served immediately or individually wrapped in parchment paper and stored in the freezer for several days.