Though some might find it self-explanatory, others are more comfortable trying something new with a few instructions, so here they are:

In a blender, drop about 1/4 cup of peanut butter—a couple extra-large spoonfuls (chunky is preferred).  Lick utensils.

Add several scoops of either chocolate ice cream OR vanilla ice cream and a liberal dose of chocolate syrup.  Lick utensils.

Add milk as necessary to achieve blendability.

Blend.

Drink.

Lick utensils.

Repeat.