Using your finger tip, coat the rim of your shake glass with marshmallow fluff. Dip the glass rim in the graham crackers crumbs to coat it. {You can place the crumbs on a plate for easy dipping.}
Place the ice cream, frozen yogurt, chocolate syrup, 1/2 cup milk, remaining graham cracker crumbs and marshmallow fluff in a blender. Blend until smooth; add more milk as needed until you reach your desired thickness.
Skewer the marshmallows and toast them on all sides over and open flame.
Pour the shake into your glass and garnish with toasted marshmallows.
Recipe Notes
You can use all vanilla ice cream if you prefer, the shake will still rock!