Invite a friend or family member (or both!) over to your residence, saying you baked a pie. If you want to bake a pie, that's fine. Otherwise, you may purchase one at a grocery store or wherever pies are sold. Then get some shaving cream and put it on top of the pie, telling your guest that it's the most delicious whipped cream.* Finally, sit back and enjoy the show. Hehe!

"Mmmmm, this Gillette Sensitive Shaving Cream with Aloe - I mean whipped cream -looks delicious!"
*If you have any concerns that your guest is on to you, feel free to put some real whipped cream on your own slice of pie, making sure to take a few bites right away so as to alleviate any suspicion. It would also be a good idea to make very loud moans of pleasure or to yell out "this is so excellent!" so as to fully convince your friend or family member that there is nothing to worry about. However, beware of Murphy's Law of Whipped Cream Pranks, in which if there is a possibility that you can accidentally eat the shaving cream tainted pie slice then you probably will.