When you look at someone in a sneaky way, after planning to for some time. Often preceeded by a courage building up moment and excecuted by sort of looking around the room like your bored then stealing a quick peak and looking away just as fast.
planned + glance = plance
I was pretty sure that sexy senior was looking at me, but i didn't want to just stare if he wasn't, i had to plance around a bit.
I saw her walking up and in my head i was already getting ready to plance.