Faerie do not need to sleep but... can you put them to sleep with The Call to Slumber? This spell is momentary, so the sleep last as long as naturally would. You merely "Control a target’s mental state (for example, awake, asleep, or confused)".
Does this spell affect faerie? And how long would it last? As in a human?
Ave Sodales,
I would say yes, a faerie may fall asleep, especially if it has something to do with its role and story theme (making it sleep naturally even if it must not). Satyrs may very well sleep after drinking, orgy or intercourse.
Note some other faeries NEED sleep and food (if they have the corresponding Flaw).
The duration of a regular nap depends the faerie nature - I tend to think Fay Snakes, Ogres, Dragons and Damsels can sleep much longer than, for example, Fay Wolves, Birds of prey or Bridge guardians.
Timing may have a role to play : I guess a Faerie bear will fall asleep in a easier way if you target it during cold winter, or the Owl of Athena may be sleepy when the sun is in the sky.