To Harry-Bethany is to put broken up cheese and onion crisps on another person's nipple(s) and then to lick or suck the crisps crumbs off. It must be performed with two or more people.
Person B:Already? I'll get the crisps and you can prepare yourself for the best Harry-Bethany of your life!
Person A:You know how I like it.
One of the participants (usually the female) crumbles up Cheese and Onion crisps onto his/her nipples. Once this has been done, the other participant licks and sucks on the nipples of the other to get all of the crisp crumbs off.
Participant 2: Ooh, lets do the Harry-Bethany. I'll get the crisps *winks*
Participant 1: You know me so well...