The Clubhouse is a shed on Liberty High School's property where the athletes take girls to party. It was Founded by Rick Wlodimierz when he was a student at Liberty High. The Athletes drug the girls and sexually assault them while they are unconscious. This practice has been allegedly going on for decades with generations of athletes participating.
The first time the Clubhouse was seen was in the first Polaroid, in the second season of 13 Reasons Why, through Polaroids anonymously given to Clay Jensen that showed two seniors in the clubhouse holding drinks in their hands and the implication is that they are drunk. The second polaroid Clay anonymously received showed Bryce Walker in The Clubhouse raping an unknown girl with the label reading 'Hannah wasn't the only one', this is later confirmed to be Chlöe Rice, his current girlfriend. The Clubhouse was only seen for the first time properly through a video taken, showing Marcus Cole and an unknown woman engaging sexually, with a crowd of athletes cheering on Marcus.
Bryce learned about The Clubhouse through Coach Rick.