Blend up the syrup, milk, avocado and cacao powder until smooth. Taste test. If it needs to be sweeter in your opinion, add maple syrup a tbsp at at time, not to exceed three additional tbsps.
Pour mixture into the popsicle mold. Freeze 30 minutes and insert sticks. Freeze at least four hours or overnight.
To remove popsicles, dip the mold into hot water (do not let water touch the top or the popsicles will melt away). Then tug a popsicle at a time, putting a release one directly into the freezer. I usually set up a cookie sheet in there with parchment paper so that when I release a pop, I can put it directly there. It will have melted slightly during the release process so this step is important to re-freeze them.
Once released and in the freezer, decide if you want to dip them. If so, microwave the chocolate chips at 60 seconds, and stir until chips are melted. Let the chocolate cool as much as possible without hardening.
Set up a cooking rack on your work table, and put parchment paper beneath it to catch drips.
Dip each popsicle into the melted chocolate. Then hold the dipped popsicle over the melted chocolate until most drips have dripped off. Then lay the dipped popsicle on the cooking rack to harden.
I normally dip three at at time, let them harden a few seconds, then return those dipped popsicles to the freezer cookie sheet.
Once all pops are dipped and frozen, store them in an airtight container in the freezer. Ours have lasted a month without freezer burn.