Watch it at 2 - 3 seconds. I -think- the Ukrainian was trying to cross over from the one cheek to the other. Will Smith was struggling and they brushed lips by accident. I think.
Anyway, here is a much more dignified and proper protocol IMO.
http://www.youtube.com/watch?v=H8VuJVffyhU
Wonderful clip. . .absolutely hilarious and true to form.
Thanks for reminding me. . .I have to dig out my Patton DVD and give it another viewing.