The amount of time allowed for spraying deodorant or cologne such as Axe or Tag (also called TSR for short). It's the responsibility of everyone around the potential offender to monitor his usage, as excess usage of body spray has been known to render potential hookups (and really anyone) unconscious. Any breaking of the three second rule is punishable by confiscation of the offender's aerosol can and/or death. This rule also applies to aerosol cans such as Febreez and Oust if these products are used in confined conditions.
-Bro 1 sprays Axe product until visibility is reduced to that of a monsoon-
Bro 2: Dude! Three second rule!
-Bro 2 seizes can from Bro 1 and inserts the still-spraying can into Bro 1's throat-