You need to keep your flirt game strong while in a long-distance relationship
While DiNozzo might not be the right fit for a long-distance relationship, that's where McGee found himself for most of Season 12. Before Delilah came back, McGee hadn't seen her for six months.
DiNozzo and Bishop suggested that McGee's work-flirting with Agent Larsen would keep his "tools sharp," so to speak. For when Delilah returned, of course.