Dammit, how did I not see this thread before I made the Nickname thread. I'll kibosh that one since this already has 2 pages of replies.
Mine have been:
-Mr. Bigggg (from my high school gf, I think I was the biggest she had seen at the time)
-Magic stick
-My big-dicked latino lover
-El Chorizo
-Chocolate popsicle (chocopop for short)
The fwb who called mine chocopop also had another fuck buddy who was huge, so she referred to him as "Peesus", because he was hung like Jesus.