The term floater describes a throw in which the club has no spin at all, it remains horizontal and pointing forward the whole time:
There are 2 schools of thought concerning how floaters should be thrown. Some jugglers hold the club near to the middle, as close to the centre of gravity as possible; others use a grip near to the end of the handle. I find it a lot harder holding the centre, especially with long handled clubs - the handles tend to hit my forearms and get in the way, and even slight errors made when releasing the club have a big effect on its rotation. I therefore recommend that you adopt the second method, the advice which follows isn't applicable if you use the central grip.
As you release each throw push your hand up as for reverse spins, but with less force. When throwing a reverse spin the object of the pushing action is to actually cause the club to turn, with floaters you should use just enough force to counteract the forward spin naturally imparted to the club by the throwing action, but not enough to actually turn it in the other direction. The push should be made with the club on the very tips of your fingers, just before it is released, rather than while you are still gripping it in your palm. Try to keep the club pointing straight forward rather than angling it toward the receiving hand as you would do normally. This eliminates the 'scooping' action required after the catch in order to point the club back in the direction it came, making the trick simpler by keeping the club's movement to a minimum between the catch and the next throw.