T.A.S = Trading Against a Swing refers to a technical set-up when a swing point (high or low) is re-tested. The re-test can be on any time-frame but typically are referenced on daily and weekly charts.
There are two possible outcomes; either the re-test results in a breakout (by breaking through the swing) or a false-breakout (in which the swing holds-up for the most part).
(All trade recommendations* involve 50 pip stop-losses.)
*Trade at your own risk!