Top Words Causing Giggles Among Pre-Teens

During the extreme boredom of my last paper, I relieved myself with old jokes from the Onion vault. Here's a gem from April 2000:

Top Words Causing Giggles Among Pre-Teens

2% Parts
1% Slot
15% Ball-peen hammer
8% Mastication
7% Receptacle
16% Titular archbishopric
13% Pu-pu platter
5% abreast
11% Lake Titicaca
12% Penal system
6% Opening
4% Moist