Forever Glue appears to be a small, white bottle with an orange top. The front side of the bottle is blue and says "Forever Glue" at the top in white. As its name states, Forever Glue has the ability to stick anything together forever. However, Forever Glue can be washed off with tears as revealed at the end of "Stuck in the Wringer."
Role in episode
After SpongeBob gets stuck in his wringer with no sign of recovery, he asks his best friend Patrick for help, though the latter, being his dumb self, only makes matters worse by using his Forever Glue to "help." Throughout the rest of the episode, SpongeBob is forced to go out in public with his wringer stuck to his body.
However, near the end of the episode, when SpongeBob and Patrick cry as a result of their friendship being brought into jeopardy, the glue dissolves and is thus revealed to not actually be permanent.
The glue's "forever" part does not really last like the name suggests, as the glue can be easily removed by tears. This has been proven at the end of "Stuck in the Wringer." Therefore, it really is not forever glue at all. Just strong, regular glue at best.
It appears that Patrick has used it before because, on the top, there is dry glue.
Its name and concept may be a parody of Krazy Glue.