From Lost Fables Wiki
Hearfelt laughter, when in a clear jar, looks like a glowing, honey-gold gas. If you put your ear to one of these jars, it's said you can almost hear the joke which spawned the laughter.
A simple alchemical windscarf, without even a catcher at the mouth will suffice to gather Heartfelt Laughter. Simply by putting the tail of the windscarf into almost any container and closing it within a day or so of it being captured, the essence of heartfelt laughter can be gathered. You can gather 4 of these per age.
Heartfelt laughter, when made into alchemical mixtures, gives a sense of joy and elation. While potions or injections of it helps to combat and cure mental effects, a paint or salve applied to the armor can block these sorts of effects. Does not combine with other alchemical ingredients beyond a base.