Make DCs (or things) bigger
K, so it only happened once, but it was pretty hilarious, or at least I thought so. My manager from work magically appeared while I was lucid, only he was abnormally short. Upon entering my dream he complained at me that because my dream made him short. So to make him shut up I stuck my thumb into my mouth and blew into it. He immediately puffed up to normal size, thanked me, and walked off.
I imagine the cartoonish "blow into thumb" technique could be useful elsewhere, but I just havent thought of where yet.