Beat heavy cream to stiff peaks in a large bowl.
Fold sweetened condensed milk and vanilla into the whipped cream gently until just combined.
Pour half the mixture into a 9x5 inch loaf pan.
Drop spoonfuls of marshmallow fluff and hot fudge over the surface, then sprinkle with half the graham crackers and chocolate chips.
Pour remaining ice cream mixture over the top and repeat with remaining marshmallow fluff, fudge, graham crackers, and chocolate chips.
Use a knife to gently swirl the toppings into the mixture, then cover tightly and freeze at least 6 hours or overnight.
Let sit at room temperature for 5 minutes before scooping.