To clarify, it's pronounced (jom-bee). and is the acronym for Jerk Off Memory Bank. This means to save an image in your mind for later self satisfaction, or perhaps sharing with another co-jerker.
Dude, when Dana bent over to pick up that pencil in the office I saw her thong slip up her pink meat curtains thru her dress. I'm sticking that in the j.o.m.b. (jom-bee) for my coffee break.