It also appears in his laundry room in "Dumped" as a clothing wringer, however, this is different from the one kept in his bathroom.
"Stuck in the Wringer"
The wringer plays a very important role in this episode. SpongeBob slips on Patrick's rubber duck and gets stuck in his wringer, which causes him to have a mishap-filled day. His problem only becomes much worse when Patrick uses his Forever Glue on it, which causes SpongeBob to be even more stuck.
This leads to a chain of misfortune for SpongeBob, resulting in him angrily lashing out at Patrick for ruining his life. Patrick runs off crying as a result, ending his friendship with SpongeBob in the progress.
Near the end of the episode, SpongeBob and Patrick cry as a result of their friendship declining, which melts the glue and frees SpongeBob. Once he is freed from the wringer, SpongeBob throws it up into the air to give Patrick a hug in celebration of their reconciliation. However, it lands and traps both of them in it, though this does not affect SpongeBob nor Patrick since they are glad to be stuck together. Patrick attempts to cause misfortune again by encouraging another usage of his Forever Glue.