A slipstream is the trailing airflow left behind a moving body. In aerodynamics, this wake can reduce drag for objects that follow closely behind the leader, which is why the term is associated with energy savings and drafting. It is different from the object itself: the slipstream is the disturbed air, not the moving body.
In cybersecurity, slipstream is mainly useful as a model for hidden follow-on effects. Attackers sometimes try to blend malicious activity into the wake of normal traffic, trusted processes, or routine user behavior so it is harder to spot. Defenders look for changes in timing, spacing, and sequence that reveal something riding behind legitimate activity. The lesson is practical: a visible action may not be the whole event, and the most important signal can be the trail it leaves behind.