Whoopie cushion cakes are great for a laugh! This is a mini cake but it can also be done with a much larger one.
Bake 1 layer of cake let it cool. Wrap and freeze for the night. zzzzzzz
In the morning carve curves into the cake top and bottom. This is give the whoopie cushion pleats.
Cover with buttercream and cover entire cake with fondant. Pinch around the edge gently. Write "old fart" or any other endearments you wish.
To make the "exit hole" I took 2 pieces of fondant cut into triangles. I pressed the edges together to create a seam and used a toothpick to keep the opening open and secure it to the cake.