I made a second version of the device to test a different sensing method. This version used high resistance switching to detect kissing. To quickly test this method out I cut a piece of copper clad board the same dimensions as the MakeyMakey, drilled some hole and etched a quick set of lips to act as the ground and input electrodes.
Using brass standoffs I connected the bottom lip to the ground bar of the pcb and the top lop to the 'up-arrow' input on the board. I edited the code and quickly got a working version up and running.
After testing with the board for a while I realized the idea of kissing copper might not be that attractive to most. So my next test will be using capacitive touch sensing to allow me to detect touch/kisses without direct contact on the electrodes.