Noun. A zoo of images one creates in his or her mind in order to be withdrawn at a later date to be used as assisistance while pounding one out. The bank is.
“yeah, that's going in the spank bank” memories of women or men kept for use in masturbatory fantasies. did you see his chest in that shirt? i'll store that one in.
Would he make a move on me? Or was he just looking to fill his spank bank with someone untouchable? A grin spread over my face—if he did come after me.
it's your "mind" bank containing images or memories specifically for masturbating.