If you want to use this trick, you've got to have the Moodlet Manager Machine.

If one of your needs is really low ,for example your hunger needs, select your Sim and choose "cure" option.

Then your needs will be refilled to its maximum level.

This is really useful when you working on something, like painting, writing and hacking.

But be careful, if you use it near a wall or other stuff, the result will deflect and it won't make your needs max, but rather super low.