The Simpsons and Sport by BarkerC

Question 10

In ~Homer vs. Patty and Selma~, Bart and Milhouse skip class on the day to sign up for new gym classes, which are first come, first serve. Lisa is worried she hasn't seen them, at which point Lewis says "If they don't show up soon, it will be T.S. for them." In this case, what is T.S.?

tethered swimming