A Dirty Jimmy is the sexual act consisting in a guy cumming all over another guy's penis, then the latter puts any spicy seasoning on his hand and masturbates his cum-drenched dick, and when the mix is homogenous, someone else sucks dry the poor fella's dick.
A: Have you ever done a dirty jimmy?
B: Last week my girl tried to pressure me into doing it, but there's no way I'm turning my dick into a nasty birthday party hot-dog.