It comes in a white bottle with an orange cap. The front side of the bottle is blue and it reads the product's name at the top in white text.
As its name states, Forever Glue has the ability to stick to anything permanently or strongly, kind of like the super glue. However, it can be washed off with tears, as revealed at the end of "Stuck in the Wringer." Therefore, it really is not "forever" glue at all, just strong, regular glue at best.
Role in series
"Stuck in the Wringer"
After SpongeBob gets stuck in his wringer with no sign of recovery, he asks Patrick for help, though the latter 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, the glue dissolves and is thus revealed to not actually be permanent.
The glue is used when SpongeBob uses Mr. Krabs' jewels on Pearl to hide her barnacles.
It appears that Patrick has used it before the events of "Stuck in the Wringer" because on the top there is dry glue.