I just learned about cone-ing .... hilarious... what will they think up next for innocent fun.
Cone-ing is a drive-thre prank whereby you do not pick up the ice cream from the cone, but grab a part of the top.
Be sure to ask that they take the napkin or paper off the cone so that when you eat it upside down, you've got a clean bite.
It's all over youtube. Here's some funny ones I found.