If you see someone walking around the Boston Red Sox clubhouse with mysterious purple spots on them, either Michael Phelps got lost on his way to the pool or NESN’s Gary Striewski is in the house.

Cupping has been practiced in one form or another since ancient China, but it became the talk of the 2016 Rio Olympics when multiple swimmers, including Phelps, were spotted with strange marks on them.

The practice is used to activate blood flow, which was very helpful for swimmers as they competed in multiple events over the course of just a few days in Rio de Janeiro. But they aren’t the only athletes using cupping for their recovery process.

Many major league pitchers also use it to activate blood flow to their arms after their outings. Therefore, Striewski decided to try it for himself, and the result was a highly entertaining segment — although being caught in torrential rain probably takes the cake — before Wednesday’s Boston Red Sox-Baltimore Orioles game, which you can see in the “Red Sox Gameday Live” video above.